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### 11th Standard CBSE Chemistry Study material & Free Online Practice Tests - View Model Question Papers with Solutions for Class 11 Session 2020 - 2021 CBSE [ Chapter , Marks , Book Back, Creative & Term Based Questions Papers - Syllabus, Study Materials, MCQ's Practice Tests etc..]

#### Class 11th Chemistry - Environmental Chemistry Case Study Questions and Answers 2022 - 2023 - by Study Materials - View & Read

• 1)

Environmental pollution is the effect of undesirable changes in our surroundings that have harmful effects on plants, animals and human beings. Even small amount of pollutants in air become significant. Some pollutants are biodegradable, e.g., discarded vegetables which rapidly break down by natural processes. DDT, plastic material, heavy metals, many chemicals, nuclear waste remain in environment for long time, are difficult to remove. Virus, bacteria cause diseases. Some of them are air borne. Some microorganisms get contaminated with water. Excessive use of fertilizers pesticides, insecticides cause soil pollution. Each household cleaning chemicals are harmful for children. Green chemistry can help to reduce pollution of air, water and soil.
(a) When does rain become acid rain?
(b) BOD, biological oxygen demand measure of organic material present in water. If BOD value is greater than 17 ppm what does it indicate? What is ideal value?
(c) Why should jet aeroplanes not fly in stratosphere?
(d) If there is enhance algae growth in water, what is its cause?
(e) Which is more suitable for dry cleaning and why?

• 2)

The table gives the tolerable limits up to which they are permitted in water according to international standards. Study the table and answer the questions based on table and related studied concepts.

 S.No Chemical Tolerable limit concentration 1 F- 1 ppm 2 Pb 50 ppm 3 Zn 5 ppm 4 Cu 3 ppm 5 Fe 0.2 ppm 6 Al 0.2 ppm 7 Mn 0.05 ppm 8 Cd 0.005 ppm 9 $\mathrm{SO}_{4}^{2-}$ < 500 ppm 10 $\mathrm{NO}_{3}^{-}$ 50 ppm 11 pH 5.5 to 9.5

(a) Name two most harmful heavy metals present in water.
(b) What is effect of higher cone  of $\mathrm{SO}_{4}^{2-}$ ?
(c) Which disease is caused by excess of $\mathrm{NO}_{3}^{-}$ ?
(d) What is use of F- ions?
(e) Which metal is safe among aU metals given in the table?
(f) Is drinking distilled water good for health?
(g) Which is better bleaching agent out of chlorine and H2 O2?

#### Class 11th Chemistry - Hydrocarbons Case Study Questions and Answers 2022 - 2023 - by Study Materials - View & Read

• 1)

Organic reactions can be classified into four main categories. Substitution reactions, addition reactions, elimination reactions and rearrangement reactions. Substitution reactions can be further classified into free radical, nucleophilic and electrophilic substitution reactions. Addition reactions can be nucleophilic as well as electrophilic addition reactions. Dehydration, dehydrohalogenation, dehalogenation are examples of elimination reactions. Conversion by ammonium cyanate to urea is an example of rearrangement reactions. Reactions are classified on the basis to nature of intermediate species formed. Mechanism of reaction is exact path followed by the reaction involving all steps showing intermediates and slowest steps of the reaction which is rate determining step. Oxidation, reduction, combustion reactions are also important in hydrocarbons.
(a) Halogenation of alkane is an example of which type of reaction?
(b) What happens when 2-methyl propane is heated with KMnO4?
(c) What type of reaction takes place when n-hexane is heated in presence of AICI3 (anhy.) and HCI?CH2 =CH2 + KCI + HzO
(d) What happens when but-2-yne reacts with H2 in presence of Lindlar's catalyst.
(e) CH3CH2C1 + KOH(alc) $\longrightarrow$ CH2 =CH2 + KCI + H2
What is type of reaction?
(f) Why do aromatic hydrocarbons undergo electrophilic substitution reaction?

• 2)

Observe the table of variation of melting and boiling point in Alkanes. Study the table and answer the questions that follow based on table and related studied concepts.
Variation of Melting Point and Boiling Point in Alkanes

 Molecular formula Name Molecular mass/u b.p./(K) m.p./(K) CH4 Methane 16 111.0 90.5 C2H6 Ethane 30 184.4 101.0 C3H8 Propane 44 230.9 85.3 C4H10 Butane 58 272.4 134.6 C4H10 2-Methylpropane 58 261.0 114.7 C5H12 Pentane 72 309.1 143.3 C5H12 2-Methylbutane 72 300.9 113.1 C5H12 2,2-Dimethylpropane 72 282.5 256.4 C6H14 Hexane 86 341.9 178.5 C7H16 Heptane 100 371.4 182.4 C5H18 Octane 114 398.7 216.2 C9H20 Nonane 128 423.8 222.0 C10H22 Decane 142 447.1 243.3 C20H42 Eicosane 282 615.0 236.2

(a) How does boiling point varies with the increase in carbon chain? Why?
(b) Why does 2, 2-dimethyl propane has lower boiling point than 2-methyl butane and n-pentane?
(c) Why is melting point of 2, 2-dimethyl propane is higher than n-pentane and 2-methyl butane?
(d) What is physical state of heptane?
(e) How does density vary with the increase in molar mass in hydrocarbons?
(f) What is physical state of C20H42(Eicosane)?

• 3)

Hydrocarbons are compounds of carbon and hydrogen only, obtained from coal and petroleum mainly which are major sources of energy. Hydrocarbons are classified as open chain, saturated (alkanes), unsaturated (alkenes and alkynes), cyclic (alicyclic) and aromatic based on structure.
Alkanes show conformational isomerism due to free rotation along C-C bond leading to staggered and eclipsed conformations of ethane. Staggered conformation is more stable. Alkenes show geometrical (Cis-trans) isomerism due to restricted rotation around carbon-carbon double bond. Benzene and benzenoid show aromatic character. They follow Huckel rule $(4 n+2) \pi$ electrons which must be delocalised. The presence of activating and deactivating groups decide the position of electrophile after electrophilic substitution. Polynuclear fused aromatic hydrocarbons have carcinogenic property. Benzene is prepared by polymerisation of ethyne and by heating sodium benzoate with soda lime.
(a) Why is staggered form of ethane more stable than eclipsed form?
(b) Out of T-butene and 2-butene which will show geometrical isomerism.
(c) Why is cis-2.-butene has higher boiling point than trans-2-butene?
(d) Why is cyclopentadienyl anion is aromatic?
(e) Why is -NO2 group m-directing towards electrophilic substitution?
(f) Convert acetylene to benzene .
(g) Sodium benzoate, on heating with soda lime gives benzene, name the reaction.

#### Class 11th Chemistry - Organic Chemistry: Some Basic Principles and Techniques Case Study Questions and Answers 2022 - 2023 - by Study Materials - View & Read

• 1)

It is essential to purify an organic compound. The method used for purification depends upon nature of compound and impurity present in it. The common methods to purify a solid is sublimation and crystallisation. Crystallisation is most common method applicable to most of solid organic compounds. Liquids are purified by simple distillation, fractional distillation, distillation under reduced pressure, steam distillation. Differential extraction is used to extract organic compound from aqueous solution. Chromatography is used to separate coloured substances from plants. Column chromatography, thin layer chromatography and partition chromatography are types of chromatography used for isolation and purification of organic compounds.
(a) Which method is used to purify camphor?
(b) How is unwanted colour from organic compounds removed?
(c) How is chloroform (Boiling point 334 K) and aniline (b.pt. 457 K) are separated? Why?
(d) Which is condensed first in fractionating column, vapours of higher boiling point liquid or lower boiling point liquid?
(e) How is glycerol purified?
(f) How is Aniline purified? Why?
(g) How are o-nitrophenol and p-nitrophenol separated? Why?

• 2)

The order of decreasing priority of some functional groups is $-\mathrm{COOH},-\mathrm{SO}_{3} \mathrm{H},-\mathrm{COOR},-\mathrm{COCl},-\mathrm{CONH}_{2}$

Observe the table based on different functional groups and their respective prefix and suffix given below and answer the questions as follow.

 Functional Group Prefix Suffix Alkane - - ane Alkane - - ene Alkane - - yne -x Halo (chloro, bromo, iodo) - -OH Hydroxy - ol Aldo or formyl - al Oxo - one $-\mathrm{C} \equiv \mathrm{N}$ Cyano nitrile -ROR Alkoxy ether -COOH Carboxy - oic acid -COOR Alkoxy carbonyl - oate -NH2 Amino - amine -NO2 Nitro - -CONH2 Carbamoyl or Amido - amide -COX Halo formyl - oyl halide -SO3H Sulpho sulphonic acid

(a) Write IUPAC Dame of HOCH2 -(CH2 )3-CH2COCH3 .
(b) What is IUPAC Dame of CH2 =CH-CH2Br. Give reason.
(c) What is IUPAC name of
(i)

(ii) CH2 =CH-CH=CH
(d) Write structural formula of 6-methyl ectan-s-ol.
(e) Write IUPAC name of
(i)

(ii)

(f) Write IUPAC name of

(g) Write structural formula of cyclohex-2-en-1-ol.

• 3)

Organic compounds are formed by covalent bonding. The nature of covalent bonding can described with the help of hybridisation, sp, Sp2 and sp3. The structure and reactivity depends upon type of bonds present in organic compounds. Organic compound can be represented by various structural formulae, Wedge and Dash formula is 3-D representation. Organic compounds can be classified on the basis of functional groups. Organic reactions mechanism are based on structure of substrate and the attacking reagent.
The intermediate formed can be free radical, carbocation, carbanion or carbene. The attacking reagent can be electrophile or nucleophile. The inductive, electromeric, resonance and hyper conjugative effect may help in polarisation of covalent bond. Organic reactions may be regarded as substitution, addition, elimination and rearrangement, oxidation and reduction reaction.
After the compound is obtained in pure state, qualitative analysis helps to detect elements present in organic compounds whereas quantitative analysis helps to find percentage of various elements. Dumas and Kjeldahl method help to determine percentage of nitrogen, Carius method for halogens and sulphur. Carbon and hydrogen are estimated by the amount of CO2 and H2Oformed. Phosphorus estimation is done by oxidising it to H3 PO4, sulphur to H2 SO4 , The percentage of oxygen is determined by taking the difference of 100 and percentage of all elements. Empirical formula gives simple ratios of elements whereas molecular formula gives exact number of atoms of each element present in a compound.
(b) Write the order of stability of carbocation.
(c) An organic compounds has 8% sulphur. What is minimum molar mass of compound?
(d) If C is 75%, H = 25%, what is molecular formula of compound?
(e) In estimation of sulphur, which compound of sulphur is formed?
(f) f Lassaigne extract of organic compound give blood-red colour with FeCI3, what does it show?
(g) Why should we add HNO3 to Lassaigne extract before testing for halogens.

#### Class 11th Chemistry - The p-block Elements Case Study Questions and Answers 2022 - 2023 - by Study Materials - View & Read

• 1)

Group 13 and 14 are p-block elements, consisting of metals, non-metals and metalloids. These elements show variable oxidation st~tes, lower oxidation state becomes more stable, when we go down the group. The combined effect of size and availability of d-orbitals influence their ability to form $\pi$ - bonds, Lighter elements form $p \pi-p \pi$ bonds where as heavier elements form $d \pi-p \pi \text { or } d \pi-d \pi$ bonds.
Boron forms electron deficient compounds. AI exhibits +3 oxidation state. Tl+ is more stable than TI3+due to inert pair effect. Carbon is typical non-metal of group 14, shows a property of catenation and forms large number of compounds. It also shows allotropy, diamond, graphite and fullerene are crystalline allotropes of carbon. Group 14 elements show +4 and +2 oxidation states. Pb2+ is more stable than Pb4+.CO and CO2 are oxides of carbon. CO2 is acidic and CO has lone pair, therefore, forms metal carbonyls. CO is deadly poisonous. CO2 is greenhouse gas. Silica, silicates and silicones are important classes of compounds of silicon.
(a) Why is Pb4+ good oxidising agent?
(b) Why is CO deadly poisonous?
(c) Why are silicones used in implants?
(d) What is use of zeolites?
(e) Why is fullerene purest allotrope of carbons?
(f) What is structure of $\mathrm{SiO}_{4}^{4}$ ?
(g) Why is NaOH not stored in glass bottles?

• 2)

Boron is element of Group 13. It is metalloid. Borax, orthoboric acid and diborane are important compounds of boron. Borax is used to prepared heat resistant pyrex glass. It is also used for cleaning metals like gold. It is also used in borax bead test to detect coloured salts in lab.
Orthoboric acid is a weak acid used as antiseptic in eye lotion. It is solid having extensive H-bonding. It acts as Lewis acid.
Diborane is a colourless, highly toxic gas. it catches fire spontaneously upon exposure to air. It burns in oxygen releasing enormous amount of energy.
(a) Why is boric acid considered as weak Lewis acid?
(b) What happens when boric acid is heated strongly?
(c) What happens when sodium hydride reacts with B2H6?
(d) What happens when sodium borohydride is reacted with I2?
(e) Give one use of NaBH4.

• 3)

Study the table of atomic and physical properties of group 14 elements and answer the questions that follow based on table and related studies concepts.
Atomic and Physical Properties of Group 14 Elements

 Property Element Carbon C Silicon Si Germanium Ge Tin Sn Lead Pb Atomic number 6 14 32 50 82 Atomic mass (g mol-1) 12.01 28.09 72.60 118.71 207.2 Electronic configuration [He]2s2 2p2 [Ne]3s 3p2 [Ar]3d104s24p2 [Kr]4d105s2 Sp2 [Xe]4f145d106s26p2 Covalent radius/pma 77 118 122 140 146 Ionic radius M4+/pmb - 40 53 69 78 Ionic radius M2+/pmb - - 73 118 119 Ionization enthalpy/kJ mol-1 $\Delta_{t} \mathbf{H}_{1}$ $\Delta_{t} \mathbf{H}_{2}$ $\Delta_{t} \mathbf{H}_{3}$ $\Delta_{t} \mathbf{H}_{4}$ 1086 2352 4620 6220 786 1577 3228 4354 761 708 1411 2942 3929 715 1450 3081 4082 1537 3300 4409 Electronegativityc 2.5 1.8 1.8 1.8 1.9 Densityd/g cm3 3.51e 2.34 5.32 7.26f 11.34 Melting point/K 4373 1693 1218 505 600 Boiling point/K - 3550 3123 2896 2024 Electrical resistivity/ ohm em (293 K) 1014 -1016 50 50 10-5 2 x 10-5

(a) Why does carbon not form C4+ ions?
(b) Why is density of lead higher than Sn?
(c) Why is melting point of TiD lowest in group 14?
(d) Which is better conductor lead or Tin and why?
(e) Why does $\mathrm{CF}_{6}^{2}$ Dot formed but $\mathrm{SiF}_{6}^{2-}$exists?
(f) Why is CO2 gas whereas Si02 solid?
(g) What is carborundum? Give its use.

#### Class 11th Chemistry - The s-Block Elements Case Study Questions and Answers 2022 - 2023 - by Study Materials - View & Read

• 1)

Group 1 and group 2 elements are called s-block elements. Their general electronic configuration is ns1 to 2. Group 1 are called alkali metals where as group 2 elements are called alkaline earth metals. They resemble with each other in many respects but differ in some of properties due to difference in valence electrons, electronic configuration and atomic size.
(a) Why are group 1 elements softer than group 2 elements?
(b) Why are group 1 elements more electropositive than group 2?
(c) Why are K, Rb and Cs used in photoelectric cells?
(d) Why is BeCI2 more covalent than LiCI?
(e) Which colour is imparted to flame by Ca2+and Ba2+?

• 2)

Study the table and answer the questions based on the table and related studied concepts.
Atomic and Physical Properties of the Alkaline Earth Metals

 Property Beryllium Be Magnesium Mg Calcium Ca Strontium Sr Barium Ba Radium Ra Atomic number 4 12 20 38 56 88 Atomic mass (g mol-1) 9.01 24.31 40.08 87.62 137.33 226.03 Electronic configuration [He]2s2 [Ne]3s2 [Ar] 4s2 [Kr] 5s2 [Xe] 6s2 [Rn] 7s2 Ionization enthalpy (I)/kJ mol-1 899 737 590 549 503 509 Ionization enthalpy (II)/kJ mol-1 1757 1450 1145 1064 965 979 Hydration enthalpy (kJ/mol) - 2494 -1921 -1577 -1443 -1305 - Metallic radius/pm 111 160 197 215 222 - Ionic radius M2+/pm 31 72 100 118 135 148 m.p./K 1560 924 1124 1062 1002 973 b.p/K 2745 1363 1767 1655 2078 (1973) Density / g cm-3 1.84 1.74 1.55 2.63 3.59 (5.5) Standard potential $\mathbf{E}^{\odot} / \mathbf{V}$ for (M2+/ M) -1.97 -2.36 -2.84 -2.89 - 2.92 -2.92 Occurrence in lithosphere 2* 2.76** 4.6** 384* 390* 10-6*

(a) Which is best non-radioactive reducing agent in Group 2? Why?
(b) Why does hydration enthalpy of bivalent cations of group 2 decrease down the group?
(c) Which element of group 2 has lowest melting points and why?
(d) Name a radioactive element of group 2
(e) Which group 2 element has lowest density?

• 3)

The first element of each group, lithium in first group and beryllium in the second group differ from rest of the elements but have similar properties to diagonally situated elements. Lithium resembles with Mg and Be resembles with Aluminium. Boron resembles with Silicon.
The compounds of alkali metals are predominantly ionic. The oxides and hydroxides are soluble in water forming strong alkalies. Important compounds of sodium includes sodium carbonate, sodium chloride, sodium hydroxide and NaHCO3 Sodium hydroxide is manufactured by Castner-Kellner process and sodium carbonate by Solvay process.
The oxides and hydroxides of group 2 elements are less basic than group 1, oxides and hydroxides. CaO, Ca(OH)2$\mathrm{CaSO}_{4} \cdot \frac{1}{2} \mathrm{H}_{2} \mathrm{O}, \mathrm{CaCO}_{3}$ and cement are industrially important compounds. Portland cement is an important 2 constructional material. It is manufactured by heating limestone and clay in a rotary kiln. The clinker obtained is mixed with 2 to 3% gypsum.
Na+,K+, Mg2+and Ca2+ are found in large amounts in biological fluids. These ions perform important biological functions such as maintenance of ion balance and nerve impulse conductions.
(a) What is cause of diagonal relationship?
(b) Why does first element of each group differ from rest of the elements?
(c) Name the product formed at anode and cathode on electrolysis of brine solution
(d) Why is BeSO4 soluble in water but BaSO4 in not?
(e) Why is gypsum is added to cement?
(f) What is role of Ca2 + in our body?
(g) What is role of Na+ in blood plasma?

#### Class 11th Chemistry - Hydrogen Case Study Questions and Answers 2022 - 2023 - by Study Materials - View & Read

• 1)

Hydrogen is most abundant element in universe. It exist in combined state in form of H2 O. On industrial scale, it is prepared by water gas shift reaction from petrochemicals. It is also obtained as a by-product of the electrolysis of brine. It has high bond dissociation enthalpy due to which it is less reactive. It forms hydrides with almost all elements. The hydrides are of three types, ionic, covalent and metallic or non-stoichiometric hydrides. It acts as reducing as well as oxidising agent. Its compound H2 O is essential for life. H2 O2 acts as oxidising, bleaching, as well reducing agent. D2 O(Heavy water is used as coolant in nuclear reactors).
(a) A 5.0 cm3 solution of H2 O2 liberates 0.508 g of iodine from KI solution. Calculate the strength of H2 O2 solution in terms of volume strength at STP.
(b) What is volume of oxygen liberated at STP from 15 mL of 20 vol. of H2 O2 of STP.
(c) How is water gas produced?
(d) What happens when steam is passed over water gas in presence of catalyst in water gas shift reaction.
The molecular formula of commercial resin used for exchange in water softening is C8H7SO3Na(Mol. Wt-206). What would be maximum uptake of Ca2 + ions by resin in mol per gram of resin?
(f) Write ionic reduction of H2O2 when it acts as reducing agent in basic medium.
(a) Acts as both oxidising as well as reducing agent
(b) Both OH bonds lie in same plane
(c) Pale blue liquid.
(d) Can be reduced by O3.

• 2)

Study the table and answer the questions that follow based in this table and related studied concepts.
Physical Properties of H2O and D2 O.

 Property H2O D2 O Molecular mass (g mol-1) 18.0151 20.0276 Melting point/K 273.0 276.8 Boiling point/K 373.0 374.4 Enthalpy of formation/kJ mol-1 -285.9 -294.6 Enthalpy of vaporisation (373K)/kJ mol-1 40.66 41.61 Enthalpy of fusion/kJ mol-1 6.01 - Temp of max. density/K 276.98 284.2 Density (298K)/g cm-3 1.0000 1.1059 Viscosity/centipoise 0.8903 1.107 Dielectric constaat/C2/N .m2 78.39 78.06 Electrical conductivity (293K/ohm-1 cm-1 ) 5.7x 10-8 -

(a) At what temperature heavy water has maximum density?
(b) What is use of heavy water?
(c) Why is water responsible for moderation of climate and body temperature of living beings?
(d) Why is boiling point of D2 O higher than H2O?
(e) What happens when Mg3N2 reacts with D2O?
(f) What is the formula of Deuterium sulphate?
(g) What happens when aluminium carbide reacts with water?

#### Class 11th Chemistry - Redox Reactions Case Study Questions and Answers 2022 - 2023 - by Study Materials - View & Read

• 1)

Redox reactions are reactions in which oxidation and reduction takes place simultaneously. Oxidation number are assigned in accordance with the set of rules. Oxidation number and ion electron methods both are used in balancing ionic equations. Redox reactions are classified as combination, decomposition, displacement and disproportionation reactions. The concept of redox couple and electrode processes is basis of electrolysis and electrochemical cells.
(a) What are oxidation number of each individual Br in Br3 O?
(b) If electrolysis of CuSO4 solution is carried out using Cu electrodes, what will be reaction taking place at anode.
(c) What is oxidation number of Cr in CrO5?
(d) Give one example of disproportionation reaction.

• 2)

Redox reactions are important class of reactions which are taking place in our daily life. Metals are good reducing agents because they can lose electrons easily whereas non-metals are good oxidising agents which can gain electrons easily. In electrolytic cells, electricity is passed to bring about redox reaction. All rechargeable batteries act as electrolytic cells while recharging. Electrochemical cells produce electricity as a result of redox reaction. Salt bridge is used in electrochemical cell to complete internal circuit and prevents accumulation of charges.
(a) What is electrochemical cell?
(b) Why is anode called oxidation electrode?
(c) Give one example of rechargeable cells widely used in vehicles.
(d) Highly reactive metals are obtained by electrolysis of their molten ores, why?
(e) What is direction of flow of current and electrons?
(f) What is standard electrode potential?
(g) What is meaning of -ve value of reduction potential? Give example.

• 3)

The standard electrode potentials at 298 K
Ions are present as aqueous species and H 2O as liquid; gases and solids are shown by g and s respectively.

 Reaction (Oxidised form + ne- $\rightarrow$ Reduced form) $\mathbf{E}^{\odot} / \mathbf{V}$ $\mathbf{F}_{2}(g)+2 e^{-} \longrightarrow 2 \mathbf{F}$ $\mathrm{Co}^{3+}+e^{-} \longrightarrow \mathrm{Co}^{2+}$ $\mathbf{H}_{2} \mathbf{O}_{2}+\mathbf{2} \mathbf{H}^{+}+\mathbf{2} e^{-} \longrightarrow \mathbf{2} \mathbf{H}_{2} \mathbf{O}$ $\mathrm{MnO}_{4}^{-}+8 \mathrm{H}^{+}+5 e^{-} \longrightarrow \mathrm{Mn}^{2+}+4 \mathrm{H}_{2} \mathrm{O}$ $\mathbf{A u}^{3+}+\mathbf{3} \boldsymbol{e}^{-} \longrightarrow \mathbf{A u}(s)$ $\mathrm{Cl}_{2}(g)+2 e^{-} \longrightarrow 2 \mathrm{Cl}^{-}$ $\mathrm{Cr}_{2} \mathrm{O}_{7}^{2-}+\mathbf{1 4 H}^{+}+6 e^{-} \longrightarrow 2 \mathrm{Cr}^{3+}+7 \mathrm{H}_{2} \mathrm{O}$ $\mathrm{O}_{2}(\mathrm{~g})+4 \mathrm{H}^{+}+4 e^{-} \longrightarrow 2 \mathrm{H}_{2} \mathrm{O}$ $\mathrm{MnO}_{2}(s)+4 \mathrm{H}^{+}+2 e^{-} \longrightarrow \mathrm{Mn}^{2+}+2 \mathrm{H}_{2} \mathrm{O}$ $\mathbf{B r}_{2}+2 e^{-} \longrightarrow 2 \mathbf{B r}^{-}$ $\mathrm{NO}_{3}^{-}+4 \mathrm{H}^{+}+3 e^{-} \longrightarrow \mathrm{NO}+\underline{2} \mathrm{H}_{2} \mathrm{O}$ $2 \mathrm{Hg}^{2+}+2 e^{-} \longrightarrow \mathrm{Hg}_{2}^{2+}$ $\mathbf{A g}^{+}+\boldsymbol{e}^{-} \longrightarrow \mathbf{A g}(\boldsymbol{s})$ $\mathbf{F e}^{3+}+e^{-} \longrightarrow \mathbf{F e}^{2+}$ $\mathrm{O}_{2}(g)+2 \mathrm{H}^{+}+2 e^{-} \longrightarrow \mathbf{H}_{2} \mathrm{O}_{2}$ $\mathbf{I}_{2}(s)+2 e^{-} \longrightarrow 2 \mathbf{I}^{-}$ $\mathbf{C u}^{+}+e^{-} \longrightarrow \mathbf{C u}(\boldsymbol{s})$ $\mathrm{Cu}^{2+}+2 e=\mathrm{Cu}(s)$ $\mathbf{A g C l}(s)+e^{-} \longrightarrow \mathbf{A g}(s)+\mathbf{C l}$ $\mathbf{A g B r}(s)+e^{-} \longrightarrow \mathbf{A g}(s)+\mathbf{B r}^{-}$ $2 \mathrm{H}^{+}+2 e^{-} \longrightarrow \mathbf{H}_{2}(g)$ $\mathbf{P b}^{2+}+2 e^{-} \longrightarrow \mathbf{P b}(s)$ $\mathrm{Sn}^{2+}+2 e^{-} \longrightarrow \operatorname{Sn}(s)$ $\mathbf{N i}^{2+}+2 e^{-} \longrightarrow \mathbf{N i}(s)$ $\mathrm{Fe}^{2+}+2 e-\mathrm{Fe}(s)$ $\mathrm{Cr}^{3+}+3 e^{-} \longrightarrow \mathrm{Cr}(s)$ $\mathbf{Z n}^{2+}+2 e^{-} \longrightarrow \mathbf{Z n}(s)$ $\mathbf{2} \mathbf{H}_{2} \mathbf{O}+\mathbf{2} e^{-} \longrightarrow \mathbf{H}_{2}+\mathbf{2} \mathbf{O H}^{-}$ $\mathbf{A l}^{3+}+\mathbf{3 e}^{-} \longrightarrow \mathbf{A l}(\boldsymbol{s})$ $\mathbf{M g}^{2+}+2 e^{-} \longrightarrow \mathbf{M g}(s)$ $\mathrm{Na}^{+}+e^{-} \longrightarrow \mathrm{Na}(s)$ $\mathrm{Ca}^{2+}+2 e^{-} \longrightarrow \mathrm{Ca}(s)$ $\mathbf{K}^{+}+e^{-} \longrightarrow \mathbf{K}(\boldsymbol{s})$ $\mathbf{L i}^{+}+e^{-} \longrightarrow \mathbf{L i}(s)$ 2.87 1.81 1.78 1.51 1.40 1.36 1.33 1.23 1.23 1.09 0.97 0.92 0.80 0.77 0.68 0.54 0.52 0.34 0.22 0.10 0.00 0.13 0.14 0.25 0.44 0.74 0.76 0.83 1.66 2.36 2.71 2.87 2.93 3.05

1. A negative $\boldsymbol{E}^{\ominus}$ means that the redox couple is a stronger reducing agent than the H+/H2 couple.
2. A positive $\boldsymbol{E}^{\ominus}$ means that the redox couple is a weaker reducing agent than the H+/H2 couple.
(a) Which is best oxidising agent and why?
(b) Which is best reducing agent and why?
(c) Calculate $\mathbf{E}^{\circ} \text { cell }$ lof Zn(s)/Zn2+(1M) II Cu2 +(aq)/Cu(s).
(d) If a redox couple has negative Eo, is it stronger or weaker reducing agent than H+/H2 couple?
(e) Arrange K, Ag, Hg, Mg, Cr in increasing order of reducing power.
(f) Arrange AI, Cu, Fe, Mg and Zn in order in which they will displace each other from salt solution.

#### Class 11th Chemistry - Equilibrium Case Study Questions and Answers 2022 - 2023 - by Study Materials - View & Read

• 1)

Equilibrium can be established for both physical and chemical processes and at equilibrium rate of forward and reverse processes are equal. Equilibrium constant (Kc) is expressed as the concentration of products divided by reactants, each raised to Stoichiometric Coefficient. Kc has fixed value of constant temperature and at this stage concentration, pressure, etc. become constant. Kp is equilibrium constant in terms of partial pressure of gases or vapours. The direction of reaction can be predicted by reaction quotient Qc and Qp Qc = Kc at equilibrium and Qp = Kp Le Chatelier's principle states 'Equilibrium' will shift in the direction so as to counter balance the effect of change in T, P and conc. The equilibrium between ions and unionised molecules in weak electrolyte is called ionic equilibrium.
(a) At a certain temperature Kc = $\frac{9}{4}$ for the reaction:
CO(g) + H2O(g) $\rightleftharpoons$ CO2 (g) + H2 (g)
If we take 10 moles of each of four gases in one litre container, what will be concentration of H2 at equilibrium?
(b) In the equilibrium CO(g) + H2O(g) $\rightleftharpoons$ CO2 (g) + H2 (g) if at a given temperature, the concentration of the reactants are increased, what will be the value of equilibrium constant Kc.
(c) If the value of an equilibrium constant for a particular reaction is 1.6 x 1012, what will be present in the system at equilibrium.
(d) The Ksp of AgCl, AgBr, AgI are 1.8 x 10-10 , 5.0 x 10-13 , 8.3 x 10-17 , which will precipitate last if AgNO3 solution is added to NaCI, NaBr. NaI?
(e) The equilibrium constant for reaction N2 (g) + 3H2 (g) $\stackrel{K_{1}}{\rightleftharpoons}$ 2NH3(g) is 49, what is equilibrium constantfor NH3(g) $\stackrel{\mathbf{K}_{2}}{\rightleftharpoons} \frac{1}{2}$ N2(g) + $\frac{3}{2}$ H2(g)?

• 2)

Observe the table of the ionisation constants of some common polyprotic acid at 298 K. Answer the questions based on this table and related studied concepts.
The Ionisatlon Constants of Some Common Polyprotic Acids (298K)

 Acid Ka1 Ka2 Ka3 Oxalic acid 5.9 x 10-2 6.4 x 10-5 Ascorbic acid 7.4 x 10-4 1.6 x 10-12 Sulphurous acid 1.7 x 10-2 6.4 x 10-11 Sulphuric acid Very large 1.2 x 10-2 Carbonic acid 4.3 x 10-7 5.6 x 10-11 Citric acid 7.4 x 10-4 1.7 x 10-5 4.0 x 10-7 Phosphoric acid 7.5 x 10-3 6.2 x 10-11 4.2 x 10-13

(a) Why is Ka1 greater than Ka2?
(b) Arrange Ka1, Ka2 and Ka3 in phosphoric acid.
(c) Why is Ka1 >>> Ka2 in sulphuric acid?
(d) What is relationship between Ka1, K,a2 and Ka3?
(e) Write expression for Ka1 and Ka2 and Ka of H2CO3
(f) What is basicity of H3 PO4?
(g) Out of oxalic acid and citric acid, which is stronger?

• 3)

Arrhenius acids give W ion in aqueous solution where as bases give OIr in aqueous solution. Bronsted acids are proton donor where as Bronsted bases are proton acceptors. Acids, on donating proton form conjugate base where as bases form conjugate acid after accepting proton. Buffer solution is a solution whose pH does not change by adding small amount of H+ or OH-. The decrease in conc. of one of the ion by adding other ions as common ion is called common ion effect. Lewis acids are electron deficient or +vely charged. Lewis bases are electron rich or negatively charged, Ksp (solubility product) is the product of molar concentration of ions raised to power number of ions per formula of the compound in sparingly soluble salt. Precipitation occurs only if ionic product exceeds solubility product. Solubility of salt decreases in presence of common ion. KW, is ionic product of water, 1 x 10-14 at 298 K. KW, increases with increase in temperature. pH is -log [H3O+] where [H3O+] = C$\alpha$ in monoprotic acid 'C' is molar cone.,'$\alpha$' is degree of ionisation. A salt is said to be hydrolysed if pH of solution changes. KH is hydrolytic constant. pH of salts of strong acid and strong base is equal to 7. pH of other salts can be 7. pH of buffer solution can be calculated with the help of Henderson equation.
pH = pKa + $\log \frac{[\text { Salt }]}{[\text { Acid }]}$
(a) What win be conjugate base of
(i) H2 SO4
(ii) H$\mathbf{C}{O}_{3}^{-}$?
(b) What are conjugate acids of
(i) $\mathbf{N H}_{2}^{-}$
(ii) NH3
(c) The conc. of [H3O+] is 4 x 10-4. What is pH of solution? [log 4 = 0.6021], log 10 = 1.
(d) Kb for NH3 is 1.80 x 10-5 .What will be Ka? [KW = 1 x 10-14]
(e) Ksp of BaSO4 is 1.0 x 10-10. What is its solubility?
(f) ) Calculate pH of buffer solution containing 0.01 M CH3COOH and 0.1 M CH3COONa,pKa = 4.75.
(g) ThepKa of CH3COOH and pKb of NH4 OH are 4.76 and 4.75 respectively. Calculate pH of CH3COONH4 solution. (PKw = 14)

#### Class 11th Chemistry - Thermodynamics Case Study Questions and Answers 2022 - 2023 - by Study Materials - View & Read

• 1)

Thermodynamics involve energy changes in chemical reactions and other processes. Internal energy is total energy stored in a substance. We can specify absolute value of volume but not the absolute value of internal energy. We can measure only change in internal energy ($\triangle$U). Work done on the system is taken as positive and work done by the system is taken as negative. Heat (q) absorbed by the system is +ve and heat given out by system is negative. $\triangle$U = q + w according to first law of thermodynamics. $\triangle$H (enthalpy change) is measured at constant pressure, $\triangle$U is measured at constant volume. $\triangle$H, $\triangle$S (entropy change), $\triangle$G (free energy change) and temperature help to decide spontaneity of the process.
(a) What is $\triangle$U in adiabatic process?
(b) If 701 J of heat is absorbed by the system and 394 J of work is done by the system. What is value of$\triangle$ U?
(c) 2 litres of an ideal gas at a pressure of 10 atm expands isothermally into vacuum until its total volume is 10 litres. How much heat is absorbed and work done in the expansion?
(d) For an equilibrium H2 O(1) $\rightleftharpoons$ H2 O(g), What are sign of $\triangle$G, $\triangle$H and $\triangle$S?
(e) For N2 O4 (g) $\rightleftharpoons$ 2NO2 (g).
(f) What is Cp- Cv equal to?
(g) State second law of thermodynamics.

• 2)

Observe the table of standard enthalpy change for fusion and vapourisation of some substances. Study the table and answer the following questions.
Standard Enthalpy Changes of Fusion and Vapourisation

 Substance Tf/K $\Delta_{f u s} \mathbf{H}^{\odot} /\left(\mathbf{k} \mathbf{J} \mathbf{m o l}^{-1}\right)$ Tb/K $\Delta_{v a p} \mathbf{H}^{\odot} /\left(\mathbf{k} \mathbf{J} \mathbf{m o l}^{-1}\right)$ N2 63.15 0.72 77.35 5.59 NH3 195.40 5.65 239.73 23.35 HCl 159.0 1.992 188.0 16.15 CO 68.0 6.836 82.0 6.04 CH3COCH3 177.8 5.72 329.4 29.1 CCl4 250.16 2.5 349.69 30.0 H2O 273.15 6.01 373.15 40.79 NaCI 1081.0 28.8 1665.0 170.0 C6H6 278.65 9.83 353.25 30.8

(a) Why is $\triangle$Hvap of NaCI highest?
(b) What is $\triangle$s for H2O(s) $\rightarrow$ H2O(I)?
(c) Which has stronger intermolecular forces, CCl4 or Acetone?
(d) calculate $\triangle$Uvap for H2O if $\triangle$Hvap = 40.66 kJ mol-1 at 373 K for 1 mole.
(e) NH3(g) $\rightarrow$ NH3 (l). What is sign of $\triangle$s?
(f) How is enthalpy of sublimation calculated?
(g) What is relationship between ionisation enthalpy and ionisation energy?

• 3)

We can measure the transfer of heat from one system to another which cause change in temperature. The magnitude of change in temperature depends upon heat capacity of the substance. The enthalpy change of reaction remains the same irrespective of number ofsteps is Hess's law.It helps to calculate enthalpy of formation, combustion and other enthalpy changes. Enthalpy change can also be calculated by using bond enthalpies. First law gives law of conservation of energy but does not give direction of reaction. Second law states, entropy of universe is continuously increasing due to spontaneous processes taking place in it. $\Delta$H and $\Delta$S (entropy change) cannot decide spontaneity of process. We need $\Delta$G (free energy change) which is -ve for spontaneous, +ve for non-spontaneous. $\Delta$G = 0 for process in equilibrium. $\Delta$G is related to equilibrium constant. If $\Delta$G = -ve, 'K' is +ve and vice versa. Third law of thermodynamics states the entropy of perfectly crystalline substance is zero at zero kelvin.
(a) We can determine $\Delta$H lattice with the help of cycle. Name the cycle.
(b) How can we calculate enthalpy of solution?
(c) What is molar heat capacity of water in equilibrium with ice at constant pressure?
(d) $\Delta \mathbf{H}_{f}^{\circ}$ of O3, CaO, Hand HI are +142.2,- 643.9,-46, +25.95 kJ mol-1. Arrange these in increasing order of stability.
(e) Standard entropy of X2 , Y2 and XY3 are 60, 40 and 50 JK-1 mol-1 respectively. For the reaction $\frac{1}{2} \mathbf{X}_{2}+\frac{3}{2} \mathbf{Y}_{2} \longrightarrow \mathbf{X Y}_{3}, \Delta \mathbf{H}=-\mathbf{3 0}$ KJ to be at what temperature, process will be at equilibrium.
(f) What are sign of $\Delta$H and $\Delta$S for process to be always spontaneous?
(g) Give mathematical expression for second law of thermodynamics.

#### Class 11th Chemistry - State of Matter Case Study Questions and Answers 2022 - 2023 - by Study Materials - View & Read

• 1)

The pressure exerted by vapours over the liquid is called vapour pressure of liquid in a closed container. When liquid and vapour phase are in equilibrium, the vapour pressure of this stage is known as equilibrium vapour pressure or saturated vapour pressure. Vapour pressure depends upon temperature. Boiling point is temperature at which vapour pressure of liquid becomes equal to atmospheric pressure.
(a) Why does water boil below 100°C at hill stations?
(b) Why does vapour pressure of sea water is lower than distilled water?
(c) Two liqurds 'X' and 'V' boil at 110°Cand 130°C respectively. Which of them has higher vapour pressure at 50°C?
(d) What is boiling point of water inside the pressure cooker?
(e) How is vapour pressure related to temperature?

• 2)

Table shows critical temperatures of some substances. Study the table and answer the questions that follow:
Critical Constants for Some Substances

 Substance Tc/K pc/bar Vc /dm3mol -1 H2 33.2 12.97 0.0650 He 5.3 2.29 0.0577 N2 126.0 33.9 0.0900 O2 154.3 50.4 0.0744 CO2 304.10 73.9 0.0956 H2O 647.7 220.6 0.0450 NH3 405.5 113.0 0.0723

(a) Why is Helium most difficult to liquefy?
(b) Out of CO2 and NH3 which will liquefy first?
(c) Critical temperature of CH4 and CO2 are -81.9°C and 31.1°C respectively. Which of these have stronger intermolecular forces of attraction?
(d) What is critical temperature?
(e) What is critical volume? How is it related to 'b' van der Waals' constant?

• 3)

Observe the graph A, B and C and answer the questions that follow based on the graph and related studied concepts.

(a) Which law is depicted by graph A?
(b) Give relationship between T1,T2 and T3 .
(c) Which law is depicted by graph B?
(d) Give mathematical formula of Charle's law
(e) Why are straight lines in graph C called isochore?
(f) What is relationship between V1, V2, V3 and V4 ?
(g) What is mathematical formula for Gay Lussac's law.

• 4)

In ionic compounds, there is electrostatic forces between oppositely charged ions. Covalent bonds are present in polar as well as non-polar molecules. Polar molecules have dipole-dipole attraction. Polar molecules with non-polar molecules have dipole-induced dipole attraction, non-polar molecules have induced dipole-induced dipole, dispersion forces (London forces). H-bonds are present in some polar molecules. Ion-dipole attraction exist between ions and polar molecules intermolecular forces are negligible in gaseous state with large intermolecular space. Interdependence of some observable properties pressure, volume, temperature and mass lead to different gas laws, Boyle's law, Charle's law, Gay-Lussac's law, Avogadro's law and Dalton's law of partial pressure. Ideal gas equation pV = nRT is followed by ideal gases. At high pressure and low temerature intermolecular forces start operatin~ strongly and molecules come close to each other. They show positive and negative deviation from ideal gas behaviour and follow van der Waals' equation. Gases can be liquefied at low temperature and high pressure. Liquids have more intermolecular forces of attraction. Some properties of liquids, e.g., surface tension and viscosity are due to strong attractive forces.
Molecules of gases are in constant random motion. Their velocity can be expressed as average velocity, root mean square velocity and most portable velocity.
(a) Under what conditions real gases show ideal gas behaviour?
(b) What type of forces of attraction exist between NO3- and water?
(c) How are different types of velocities related to molar mass?
(d) A gas at 350 K and 15 bar has molar volume 20% less than that for an ideal gas under the same conditions. What is value of 'Z'?
(e) Why is HF liquid, HCI, HBr, HI are gases?
(f) How is pressure of dry gas calculated?
(g) What is Boyle's temperature?

#### Class 11th Chemistry - Chemical Bonding and Molecular Structure Case Study Questions and Answers 2022 - 2023 - by Study Materials - View & Read

• 1)

The attractive force which holds the two atoms together is called chemical bond. Covalent bond is formed by equal sharing of electrons. Coordinate bond is formed by unequal sharing of electrons. Ionic bond is formed by transfer of electrons from one atom to another. Octet rule, although very useful but it is not universally applicable. According to valence bond theory, covalent bond is formed by overlapping of half filled atomic orbitals resulting in lowering of energy and more stability. Bond order is the number of bonds between atoms in a molecule. Higher the bond order, more will be stability and bond dissociation enthalpy but smaller bond length. Polarity of covalent bond depends upon difference in electronegativity. Covalent character of bond depends upon polarising power, smaller cation and bigger anions have higher polarising power. VSEPR theory helps to predict shapes of molecules.
(a) Write the, electron dot structure of N2O.
(b) What are ions present in CsI3?
(c) Out of CN+, CN-, NO, which has highest bond order?
(d) What is correct order of repulsion bp - bp, lp - lp and lp - bp?
(e) Draw the structure of XeOF4 on the basis of VSEPR theory.
(f) Which out of B2 ,CO, $\mathrm{O}_{2}^{2-}$ and NO+ are paramagnetic and why?

• 2)

An ionic compound has 3-D crystal lattice in which positive and negative charges are equal. The crystal lattice is stabilised by enthalpy of lattice formation, bond length, bond angle, bond enthalpy, bond order and bond polarity have significant effect on properties of compounds. All the properties of certain compounds cannot be explained by single structure, more than one structure of a compound to explain its property are called resonating structures.
Dipole moment depends upon polarity and shapes of molecules. Shapes of molecules can be determined by VSEPR theory as well as hybridisation sp, Sp2, Sp3, Sp3d, Sp3 d2 are linear, trigonal planar, tetrahedral, trigonal bipyramidal and octahedral geometery respectively. Hydrogen bond is formed between hydrogen and F, O, N. Intra-molecular H-bonding is within the molecules which is weaker than inter molecular H-bonding, between the molecules.
(a) Why does CO2 have zero dipole moment?
(b) What is hybridisation of 'S' in SF6 and its shape?
(c) Why do all bonds in $\mathrm{CO}_{3}^{2-}$ have equal bond length?
(d) Why is o-nitropbenol steam volatile, p-nitropbenol is not?
(e) Wby is bond angle in H2 O is more tban H2 S?
(f) Why is  bond $\sigma$ stronger than $\pi$-bond?
(g) Arrange NaCl, NaBr, NaF. NaI in increasing order of ionic character.

• 3)

Table shows the molecular orbital occupancy and molecular properties for B2, C2, N2, O2, F2, and Ne2. Observe this figure and answer the questions based on this diagram and related studied concepts.
MO occupancy and molecular properties for B2 through Ne2.

(a) Why does bond enthalpy of N2 is higher than O2?
(b) Why is Ne2 not formed according to M.O. theory?
(c) Why F2 diamagnetic where as O2 paramagnetic?
(d) Arrange B2, C2, N2, O2, F2 in increasing order of stability. Give reason.
(e) Why is F2 more reactive than O2 ?
(f) Arrange B2, C2, N2, O2, Fin increasing order of bond length.
(g) What is speciality of double bond in C2?
(h) How are C2 and Limolecules detected?

#### Class 11th Chemistry - Classification of Elements and Periodicity in Properties Case Study Questions and Answers 2022 - 2023 - by Study Materials - View & Read

• 1)

Modern periodic table arranges the elements in the increasing order of atomic number. It has 18 groups and 7 periods. Atomic numbers are consecutive in a period and increases in group in a pattern. Elements are divided into four blocks, s-block,p-block, d-block andf-block based on their electronic configuration. 78% of elements are metals, about 20 elements are non-metals and few elements like B, Si, Ge, As are metalloids. Metallic character increases down the group but decreases along the period from left to right. The physical and chemical properties vary periodically with their atomic numbers.
Periodic trends are observed in atomic size, ionisation enthalpies, electron gain enthalpies, electronegativity and valence. Oxides of metals are basic, some are amphoteric. Non-metals form acidic oxides, some form neutral oxides. s-block elements are soft, highly reactive, do not show variable oxidation states. p-block elements are metals, non-metals as well as metalloids, show variable oxidation states, exist as solids, liquids and gases. d-block elements are metals, form coloured ions, show variable oxidation states, have high melting and boiling points. Lanthanoids and actinoids are f-block elements, form coloured ions. All actinoids are radioactive.
(a) Name the elements which belong to d-block but are not transition metals.
(b) What are representative elements?
(c) What is difference between oxidation states of p-block and d-block elements?
(d) Which group elements are most electropositive and why?
(e) What happens to reactivity down the group 17?
(f) What type of compounds are formed by element belonging to group 14 and third period? Identify the element.
(g) What is formula of compound formed between AI and S

• 2)

The atomic and ionic radii decrease with increase in atomic number along a period from left to right. Atomic size and ionic size increases down the group.
Ionisation enthalpy decreases down the group and increases along a period from left to right. It also depends upon shielding effect as well as stability of electronic configuration.
Electronegativity decreases down the group but increases along the period.
(a) Arrange the elements of second period in increasing order of first ionisation enthalpy.
(b) Arrange the elements of group 13 in increasing order of atomic size.
(c) Select the' amphoteric oxides among the following:
NO, B2O3, Cr 2O3, BeO, ZnO, CO2 , Al2 O3
(d) For an element I.E1 = 738 kJ mol-1, IE2 = 1450 kJ mol-1, IE3 = 7700 kJ mol-1, IE4 = 1.1 x 10 4 kJ mol-1. Name the main group to which element belong. Why?

• 3)

Observe the group shown in figure and answer the questions that follow based on the graph and related studied concepts.

(a) Which group elements have lowest ionisation enthalpy and why?
(b) Which group element have highest ionisation enthalpy and why?
(c) Why is ionisation enthalpy of Be more than B?
(d) Why does 'N' have higher ionisation enthalpy than O?

• 4)

Study the table of electron gain enthalpies of some main group elements and answer the questions that follow based on table and related concepts.

 Group 1 $\Delta_{\mathrm{eg}} \mathbf{H}$ Group 16 $\Delta_{\mathrm{eg}} \mathbf{H}$ Group 17 $\Delta_{\mathrm{eg}} \mathbf{H}$ Group 0 $\Delta_{\mathrm{eg}} \mathbf{H}$ H -73 He +48 Li -60 O -141 F -328 Ne +116 Na -53 S -200 CI -349 Ar +96 K -48 Se -195 Br -325 Kr +96 Rb -47 Te -190 I -295 Xe +77 Cs' -46 Po -175 At -270 Rn +68

(a) Why do group 1 elements have low electron gain enthalpies?
(b) Why is electron gain enthalpy of sulphur more than oxygen?
(c) Why do noble gases have +ve electron gain enthalpies?
(d) Arrange P, S, CI, F is increasing order of electron gain enthalpeis.

• 5)

Study the table 1 and 2 related to electronegativity values along the period 2 and 3 Group 1 and 17 and answer the questions that follow based on these.
Electronegativity Values (on Pauling scale) Across the Periods

 Atom (Period II) Li Be B C N O F Electronegativity 1.0 1.5 2.0 2.5 3.0 3.5 3.0 Atom (period III) Na Mg AI Si P S Cl Electronegativity 0.9 1.2 1.5 1.8 2.1 2.5 3.0

Electronegativity Values (on Pauling scale) Down a Family

 Atom (Group I) Electronegativity Value Atom (Group XVII) Eledronegativity Value Li 1.0 F 4.0 Na 0.9 CI 3.0 K 0.8 Br 2.8 Rb 0.8 I 2.5 Cs 0.7 At 2.2

(a) How does electronegativity varies along a period and why?
(b) Why does K and Rb have same electronegativity although Rb is bigger than K?
(c) Why does electronegativity decrease down the group?
(d) Why is CsF most ionic?
(e) Why is H- ion bigger than F- ion?
(f) Why is Lil covalent?
(g) Why is CI2 O7 more acidic than Cl2O5?

#### Class 11th Chemistry - Structure of Atom Case Study Questions and Answers 2022 - 2023 - by Study Materials - View & Read

• 1)

Orbitals are region or space wher.e there is maximum probability of finding electrons. Qualitatively, these orbitals can be distinguished by their size, shape and orientation. An orbital of small size means there is more chance of finding the electron near the nucleus. Shape and orientation means the direction in which probability of finding electron is maximum. Atomic orbitals can be distinguished by quantum numbers. Each orbital is designated by three quantum numbers n, I and m1 (magnetic quantum number) which define energy, shape and orientation but these are not sufficient to explain spectra of multi-electrons atoms. Spin quantum number (ms ) determines the spin of electron. Spin angular momentum of electron has two orientations relative to chosen axis which are distinguished by spin quantum numbers ms which can take values +1/2 and -1/2.

 Value of 'l' 0 1 2 3 4 Notation for subshell s p d f g

(a) How many orbitals are associated with n = 3?
(b) Describe the orbitals represented by (i) n = 2, l = 1 (ii) n = 4, l = 0.
(c) How many electron are possible in an orbital? Why?
(d) What is shape of 's' and 'p' orbitals?
(e) Name two d-orbitals which are on axis.

• 2)

The plots of (a) orbital wave function $\Psi$(r) and (b) the variation of probability density$\Psi$ 2(r) as function of distance'r' of the electron from the nucleus for Is and 2s orbitals are shown in the figure. Answer the questions as follows based on graph and related studied concepts.

(a) What is meant by$\Psi$?
(b) What is meant by $\Psi$2?
(c) What happens to probability density in Is orbital?
(d) What happens to $\Psi$ 2 in '2s' orbital?
(e) What are nodes?
(f) How many nodes are 1s, 2s, 3s orbitals?
(g) What are angular nodes?
(h) How many radial and angular nodes are there in 3d orbital?

• 3)

Bohr's model explained electrons can revolve only in certain permitted orbits whose angular momentum is integral multiple of h/2$\pi$, associated with fixed amount of energy. Bohr theory could successfully explain stability of atoms and spectrum of unielectron species. Hydrogen spectrum consist of Lyman, Balmer, Paschen, Brackett and Pfund series. Bohr's theory could not explain spectrum of multi-electron species, Stark effect, Zeeman effect, dual nature of matter, de Broglie equation and Heisenberg uncertainty principle which lead to orbital concept. Electrons were filled in orbitals according to Autbau's principle, Hund's Rule and Pauli's exclusion principle. Each electron is identified by four quantum numbers n, I, ml and ms out which n, I, ml were derived from Schrodinger's wave equation. Half filled and completely filled orbitals are more stable due to exchange energy and symmetrical distribution of electrons.
(a) Heat treatment of muscular pain involves radiation of wavelength 900 nm which spectral line of H-atom is suitable for this purpose.
(b) Arrange 4d, 3d, 4p and 3p in increasing order of energy.
(c) What is name of spectrum of radiation emitted by substance that has absorbed radiation?
(d) What rules out the probability of existence of definite path of electrons?
(e) State de Broglie equation.
(f) The angular momentum of d-orbital is equal to?
(g) State Pauli exclusion principle.

#### Class 11th Chemistry - Some Basic Concept of Chemistry Case Study Questions and Answers 2022 - 2023 - by Study Materials - View & Read

• 1)

Stoichiometry is a section of chemistry that involves calculation based on chemical equations. Chemical equations are governed by laws of chemical combination. Mass of reactants is equal to mass of products. Compound obtained from different methods contain the same elements in the fixed ratio by mass. Mole is a counting unit, equal to 6.022 x 1023 particles.
One mole is also equal to molar mass expressed in grams. One mole of every gas at STP has volume equal to 22.4 L. The reacting species which are consumed in the reaction completely is called limiting reagent which decides amount of products formed. Concentration of solution is expressed in terms of molarity, molality and mole fraction.
(a) Calculate number of moles of NH3 formed by reaction of 2 moles of N2 and 2 moles of H2.
$\mathbf{N}_{2}(g)+3 \mathbf{H}_{2}(g) \longrightarrow 2 \mathrm{NH}_{3}(g)$
(b) Calculate number of electrons in 18 g of H2 O. [Atomic number of H = 1 ,O = 8]
(c) Calculate the molality of 1 M NaCI solution having density 1.10 g cm-3. (Molar mass = 58.5 g mol-1)
(d) Define mole fraction.
(e) In aqueous solution of glucose Xglucose = 0.1, what is XH2O = ?

• 2)

In the table given below to illustrate precision and accuracy. Study the table and answer the questions based on the table and related studied concepts.
Data to Illustrate Precision and Accuracy

 Measurement in g I II III Average student A 0.521 g 0.515 g 0.509 g 0.515 g student B 0.516 g 0.515 g 0.514 g 0.515 g student C 0.521 g 0.520 g 0.520 g 0.520 g

(a) What is meant by precision?
(b) What is accuracy?
(c) If actual mass of a piece of metal is 0.520 g, data for which student is neither precise nor accurate.
(d) Which student data is precise but not accurate?
(e) The data of which student is both precise and accurate?
(f) How many significant figures are in 0.520?
(g) What is scientific notation for 0.520?

• 3)

Chemistry play an important role in human needs for food, health care products and improving life. Cis platin and taxol are used in chemotherapy, AZT (Azidothymidine) is used for AIDS. SI units are international units of measurement. Matter is classified into elements, compounds and mixtures, which can be homogeneous as well as heterogeneous. A mixture can be separated by physical methods, compounds can be separated by chemical methods only. Atomic mass is average of masses of isotopes depending upon their natural abundance. Empirical formula is calculated with the help of percentage composition of elements in a compound and molecular mass helps to calculate molecular formula. A chemical equation must be balanced so as to follow laws of chemical combination.
(a) Express 2.54 mm into S.I units.
(b) Out of milk, diamond, air, petrol which is pure substance?
(c) Balance the equation: NO2 + H2$\rightarrow$ HNO3 + NO
(d) What is percentage of Na in Na2CO3 ? (Na = 23u, C = 12, O = 16u)
(e) ${ }_{17}^{35} \mathrm{Cl} \text { and }{ }_{17}^{37} \mathrm{Cl}$ are in ratio of 3 : 1 in nature. What is atomic mass of CI?
(f) What is empirical formula of C6H12O6?
(g) Chlorophyll contains 2.68% magnesium atoms. Calculate mass of magnesium atoms in 2 g of chlorophyll.

#### 11th Standard CBSE Mathematics Public Exam Model Question 2020 - by Ashutosh Saran - Gurgaon - View & Read

• 1)

One mole of CO2 contains

• 2)

de Broglie equation is

• 3)

The highest ionization energy is exhibited by

• 4)

The axial overlap between the two orbitals leads to the formation of a:

• 5)

Which of the following is the correct mathematical relation for Charles law at constant pressure?

#### 11th Standard CBSE Chemistry Public Exam Sample Question 2020 - by Ashutosh Saran - Gurgaon - View & Read

• 1)

How many grams are contained in 1 gram atom of Na?

• 2)

The orbital with n = 3 and 1 = 2 is

• 3)

What is the electronic configuration of the elements of group 14?

• 4)

Which one is diamagnetic among NO, NO and NO-?

• 5)

At constant temperature, the pressure of the gas is reduced to one-third, the volume

#### 11th Standard CBSE Chemistry Public Exam Important Question 2019-2020 - by Ashutosh Saran - Gurgaon - View & Read

• 1)

The mass of an atom of nitrogen is

• 2)

In a sodium atom (atomic number = 11 and mass number = 23) and the number of neutrons is

• 3)

In halogens, which of the following, increases from iodine to fluorine?

• 4)

The species CO, CN- and N2 are

• 5)

Viscosity of a liquid is a measure of

#### 11th Standard Chemistry Board Exam Sample Question 2020 - by Ashutosh Saran - Gurgaon - View & Read

• 1)

The empirical formula of sucrose is

• 2)

Cathode rays are deflected by

• 3)

Which of the following is arranged in order of increasing radius?

• 4)

The molecule Ne2 does not exist because

• 5)

With rise in temperature, the surface tension of a liquid

#### 11th Standard Chemistry Board Exam Model Question 2019-2020 - by Ashutosh Saran - Gurgaon - View & Read

• 1)

12 g of Mg will react completely with an acid to give:

• 2)

The energy needed to remove a single electron (most loosely bound) from an isolated gaseous atom is called

• 3)

In halogens, which of the following, increases from iodine to fluorine?

• 4)

Out of the following, intramolecular hydrogen bonding exists in

• 5)

The cleansing action of soaps and detergents is due to

#### CBSE 11th Chemistry - Public Model Question Paper - by Ashutosh Saran - Gurgaon - View & Read

• 1)

3 L water is added to 2 L of 5 M HCl. What is the molarity of HCl in the resultant solution?

• 2)

Air contains about 99% of Nand O2 gases. Why do not they combine to form NO under the standard conditions? Standard Gibbs energy of formation of NO (g) is 86.7 kJ mol-1.

• 3)

what is the nature of 'photochemical smog'?

• 4)

What is the significance of wave function $\Psi$ in the Schrodinger wave equation?
What is an atomic orbital? Why $\Psi$ is called orbital wave function?

#### CBSE 11th Chemistry - Some Basic Concept of Chemistry Model Question Paper - by Ashutosh Saran - Gurgaon - View & Read

• 1)

One mole of CO2 contains

• 2)

5.6 litres of oxygen at NTP is equivalent to

• 3)

12 g of Mg will react completely with an acid to give:

• 4)

The number of significant figures in 0.0101 is

• 5)

The mass of an atom of nitrogen is

#### CBSE 11th Chemistry - Full Syllabus One Mark Question Paper with Answer Key - by Ashutosh Saran - Gurgaon - View & Read

• 1)

One mole of CO2 contains

• 2)

5.6 litres of oxygen at NTP is equivalent to

• 3)

Which of the following has the highest mass?

• 4)

The number of significant figures in 0.0101 is

• 5)

The mass of an atom of nitrogen is

#### CBSE 11th Chemistry - Full Syllabus Five Marks Questions - by Ashutosh Saran - Gurgaon - View & Read

• 1)

How many atoms of He are present in 52 $\mu$ of He?

• 2)

Insulin contains 4.5 % sulphur. Calculate the minimum molecular mass of sulphur.

• 3)

Calcium carbonate reacts with aqueous HCI to give CaCL2 and CO2 according to the reaction given below CaCO3(s) + 2HCI(aq) $\longrightarrow$CaCl2(aq) + CO2(g) + H2O(l)
What mass of CaCl2 will be formed when 250 mL of 0.76 M HCI reacts with 1000 g of CaCO3? Name the limiting reagent. Calculate the number of moles of CaCL2 formed in the reaction.

• 4)

A neutral atom of an element has 2K, 8L and 5M electrons. Find out the following.
Valency of the element.

#### CBSE 11th Chemistry - Full Syllabus Four Marks Questions - by Ashutosh Saran - Gurgaon - View & Read

• 1)

Convert the following into basic units.
15.5 $\mu s$

• 2)

Calculate
(5.7 x 10-5$\div$ (4.2 x 10-3)

• 3)

The density of 3 M solution of Na Cl is 1.25 g mL-1. Calculate molality of the solution.

• 4)

Assuming the density of water  to be 1g/cm3, calculate the volume occupied by one molecule of water.

• 5)

50.0 kg of ${ N }_{ 2 }(g)$ and 10.0 kg of ${ H }_{ 2 }(g)$ are mixed to produce $NH_{ 3 }(g)$formed. Identify the limiting reagent in the productuion of $NH_{ 3 }$ in this situation.

#### CBSE 11th Chemistry - Full Syllabus Three Marks Questions - by Ashutosh Saran - Gurgaon - View & Read

• 1)

How many amny significant figures present in the following? "5005"

• 2)

Write the complete symbol for the atom with the given number (Z) and atomic mass (A). Z = 92, A = 233

• 3)

The quantum number of six electrons are given below. Arrange them in order of increasing energies. if any of these combinations(s) has/have the same energy lists. $n=4,l=1,{ m }_{ 1 }=0,{ m }_{ s }=+\cfrac { 1 }{ 2 }$

• 4)

With what 7'elocity must an electron travel so that its momentum is equal to that of a photon of wavelength = 5200 $\mathring { A }$ ?

• 5)

What do you understand by isoelectronic species? Name a species that will be isoelectronic with the following atom or ion. Ar

#### CBSE 11th Chemistry - Full Syllabus Two Marks Questions - by Ashutosh Saran - Gurgaon - View & Read

• 1)

Convert the following into kg. "0.91 x 10-27 g( mass of electron)"

• 2)

If the concentration of glugose (C6H12O6) in blood is 0.9 g L-1, what will be the molarity of glugose blood?

• 3)

Express the following in SI unit. "5 feet 2 inch"

• 4)

How many oxygen atoms are there in 18 g of water?

• 5)

What would be IUPAC names and symbols for elements with atomic numbers 122,127,135,149 and 150?

#### CBSE 11th Standard Chemistry - The p-block Elements Five Marks Model Question Paper - by Amit Pandya - Varanasi - View & Read

• 1)

What are the allotropes? Sketch the structure of two allotropes of carbon namely diamond and graphite.What is the impact of structure on physical properties of two allotropes?

• 2)

What happens when borax is heated strongly?

• 3)

Complete the following reactions
$CO+{ H }_{ 2 }\xrightarrow [ ZnO,{ Cr }_{ 2 }{ O }_{ 3 } ]{ 200 \ atm, \ 675K }$

• 4)

Complete the following reactions
${ CaCO }_{ 3 }(aq)+{ CO }_{ 2 }(excess)\longrightarrow$

• 5)

What happens when aluminium is treated with dilute NaOH?

#### CBSE 11th Standard Chemistry - Organic Chemistry: Some Basic Principles and Techniques Five Marks Model Question Paper - by Amit Pandya - Varanasi - View & Read

• 1)

An organic compound contains 69% carbon and 4.8% hydrogen, the remainder being oxygen. Calculate the masses of carbon dioxide and water produced when 0.20 g of this compound is subjected to complete combustion.

• 2)

Explain why ${ \left( { CH }_{ 3 } \right) }_{ 3 }\overset { + }{ C }$ is more stable than ${ CH }_{ 3 }\overset { + }{ C } { H }_{ 2 }$ and $\overset { + }{ C } { H }_{ 3 }$is the least stable cation.

• 3)

Sohan was very upset from last few days when he came to know that his father is alcoholic (takes alcohol).He knows about the side effects of the alcohol so want to keep away his father from it.He decided to talk about this with his father.When he asked his father about it, he told him, that he is not alcoholic, only occasionally he takes it but of Sohan does not even want him to ever touch it.
What values are possessed by Sohan and his father?

• 4)

Give condensed and bond line structural formulas and identify the functional group(s) present, if any, for: 2, 2, 4-Trimethylpentane

• 5)

Explain the terms inductive and electromeric effects. Which electron displacement effect explain the following correct orders of acidity of the carboxylic acids?
(a) Cl3CCOOH > Cl2CHCOOH > ClCH2COOH
(b) CH3CH2COOH > (CH3)2CHCOOH > (CH3)3C.COOH

#### 11th Standard CBSE Chemistry - Hydrocarbons Five Marks Model Question Paper - by Amit Pandya - Varanasi - View & Read

• 1)

Arrange the following set of compounds in order of their decreasing relative reactivity with an electrophile, E+.
(i) Chlorobenzene, 2, 4-dinitrochlorobenzene, p-nitrochlorobenzene
(ii) Toluene,
$p-{ H }_{ 3 }C-{ C }_{ 6 }{ H }_{ 4 }-{ NO }_{ 2 },$
$p-{ O }_{ 2 }N-{ C }_{ 6 }{ H }_{ 4 }-{ NO }_{ 2 }$

• 2)

Write IUPAC names of the products obtained by the ozonolysis of the following compounds:
(i) Pent-2-ene
(ii) 3, 4-Dimethylhept-3-ene
(iii) 2-Ethylbut-1-ene
(iv) 1-Phenulbut-1-ene.

• 3)

How will you convert benzene into
(i) p-nitrobromobenzene
(ii) m-nitrochlorobenzene
(iii) p-nitrotoluene
(iv) acetophenone?

• 4)

Addition of HBr to propene yields 2-bromopropane, while in presence of benzoyl peroxide, the same reaction yields 1-bromopropane. Explain and give mechanism.

• 5)

How will you convert the following compounds into benzene?
(i) Ethyne
(ii) Ethene
(iii) Hexane.

#### 11th Standard CBSE Chemistry - Environmental Chemistry Five Marks Model Question Paper - by Amit Pandya - Varanasi - View & Read

• 1)

What is 'Acid Rain'? How is it harmful to the environment?

• 2)

What is photochemical smog? What are its effects? How can it be controlled?

• 3)

(a) Define eutrophication and pneumoconiosis.
(b) Write difference between photochemical and classical smog.

• 4)

Have you ever observed any water pollution in your area? What measures would you suggest to control it?

• 5)

Do you observe any soil pollution in your neighbourhood? What efforts will you make for controlling the soil pollution?

#### CBSE 11th Chemistry - Environmental Chemistry Four and Five Marks Questions - by Ashutosh Saran - Gurgaon - View & Read

• 1)

How is the temperature effected as we go up the earth's surface? Explain

• 2)

It is advised not to sleep in a closed room with burning coke angithi to warm up. Explain.

• 3)

Sonu and Nilesh were friends. In winters, one day when they were going to school at 10:00 am Sonu felt irritation in his eyes and throat. He was also unable to breath.
Nilesh immediately took him to a doctor. Doctor gave him the proper remdy. When he became well, Nilesh asked reason for this Doctor answered him satisfactorily.
(i) Can you guess what reason was given by the doctor for the illness of Sonu.
(ii) Why such kind of polluting atmospheric change occurs?
(iii) What should be done to prevent the formation of smog?
(iv) What values are possessed by Nilesh?

• 4)

How carbon monoxide acts as a poison for human beings?

• 5)

What is 'Acid Rain'? How is it harmful to the environment?

#### CBSE 11th Chemistry - Hydrocarbons Four and Five Marks Questions - by Ashutosh Saran - Gurgaon - View & Read

• 1)

Which of the following compounds will show cis-trans isomerism?
(CH3)2C=CH-C2H5

• 2)

Which of the following compounds will show cis-trans isomerism?
CH2=CBr2

• 3)

Write chemical equations for the combustion reaction of the following hydrocarbons.
(i) Butane
(ii) Pentene
(iii) Hexyne
(iv) Toluene

• 4)

Arrange the following set of compounds in order of their decreasing relative reactivity with an electrophile, E+.
(i) Chlorobenzene, 2, 4-dinitrochlorobenzene, p-nitrochlorobenzene
(ii) Toluene,
$p-{ H }_{ 3 }C-{ C }_{ 6 }{ H }_{ 4 }-{ NO }_{ 2 },$
$p-{ O }_{ 2 }N-{ C }_{ 6 }{ H }_{ 4 }-{ NO }_{ 2 }$

• 5)

Write IUPAC names of the products obtained by the ozonolysis of the following compounds:
(i) Pent-2-ene
(ii) 3, 4-Dimethylhept-3-ene
(iii) 2-Ethylbut-1-ene
(iv) 1-Phenulbut-1-ene.

#### CBSE 11th Chemistry - Organic Chemistry: Some Basic Principles and Techniques Four and Five Marks Questions - by Ashutosh Saran - Gurgaon - View & Read

• 1)

An organic compound contains 69% carbon and 4.8% hydrogen, the remainder being oxygen. Calculate the masses of carbon dioxide and water produced when 0.20 g of this compound is subjected to complete combustion.

• 2)

Explain why ${ \left( { CH }_{ 3 } \right) }_{ 3 }\overset { + }{ C }$ is more stable than ${ CH }_{ 3 }\overset { + }{ C } { H }_{ 2 }$ and $\overset { + }{ C } { H }_{ 3 }$is the least stable cation.

• 3)

Sohan was very upset from last few days when he came to know that his father is alcoholic (takes alcohol).He knows about the side effects of the alcohol so want to keep away his father from it.He decided to talk about this with his father.When he asked his father about it, he told him, that he is not alcoholic, only occasionally he takes it but of Sohan does not even want him to ever touch it.
What is the main constituent of alcoholic beverages?

• 4)

Sohan was very upset from last few days when he came to know that his father is alcoholic (takes alcohol).He knows about the side effects of the alcohol so want to keep away his father from it.He decided to talk about this with his father.When he asked his father about it, he told him, that he is not alcoholic, only occasionally he takes it but of Sohan does not even want him to ever touch it.
Write the IUPAC name and hybridization of this main constituent.

• 5)

Mr.Sing altered the amount of cheque and was caught by police. Chromatography is an important technique extensively used to separate a mixture into their components to purify compounds and also to test the purity of compounds. If any cheque is written in a particular ink and somebody else alters it with another ink, it can be detected with the help of chromatography.
What values are not possessed by Mr.Sing involved in forgery?

#### CBSE 11th Chemistry - The p-block Elements Four and Five Marks Questions - by Ashutosh Saran - Gurgaon - View & Read

• 1)

Among group 14 elements name most metallic element

• 2)

Among group 14 elements name  the elements having tendency to from $p\pi -p\pi$ bonds.

• 3)

Carbon form covalent compounds whereas lead form ionic compounds.why?

• 4)

A colorless aqueous solution on adding water and on heating gave a white NH4Cl and NH4OH in excess resulted in the dissolution of some of the precipitate and a gelatinous precipitate is obtained.what is the hydroxide formed in aqueous solution?

• 5)

Aluminium dissolves in mineral acids and aqueous alkalies and thus shows amphoteric character.A piece of aluminum foil is treated with dilute hydrochloric acid or dilute sodium hydroxide solution in a test tube and on bringing a burning matchstick near the mouth of the test tube, a pop sound indicates the evolution of hydrogen gas.The same activity when performed with concentrated nitric acid, reaction doesn't proceed, Explain the reason.

#### CBSE 11th Chemistry - The s-Block Elements Four and Five Marks Questions - by Ashutosh Saran - Gurgaon - View & Read

• 1)

Explain why ?
The crystalline salts of alkaline earth metals contain more water of crystallisation than the corresponding alkali metal salts.

• 2)

Dr.Sharma , cardiologist suggested his patienta to take more potassium ions for healthy heart. potassium ions are the most abundant cations within cell fluids, where they activate many enzymes, participate in the oxidation of glucose to pro duse ATP While sodiun ions are responsible for the transmission for nerve signals. It  intake of potassium , harmful for our body?

• 3)

Dr.Sharma , cardiologist suggested his patienta to take more potassium ions for healthy heart. potassium ions are the most abundant cations within cell fluids, where they activate many enzymes, participate in the oxidation of glucose to pro duse ATP While sodiun ions are responsible for the transmission for nerve signals. What are the sources of potassium ?

• 4)

Give the reson for following Potassium carbonate cannot be prepared by Solvay ammonia process.

• 5)

Reema takes milk every day . She also take curd and other milk products.She takes green leafy vegitables and fruits also. An adult body contains about 25g of magnesium and 1200 g of calcium and 5 g of iron .these elements must be a part of our diet. All enzymes that utilize ATP in phosphate transfer required magnesium as co-factor. the main pigment for the absorption of light in plants is chlorophyll, which contains magnesium. were as Anita does not like milk and takes lot of junk food.

Why should we take green leafy vegitables in our dite?

#### CBSE 11th Chemistry - Hydrogen Four and Five Marks Questions - by Ashutosh Saran - Gurgaon - View & Read

• 1)

An ionic hydride of an alkali metal has significant covalent character and is almost unreactive towards oxygen and chlorine. This is used in the synthesis of other useful hydrides. Write its reaction with ${ Al }_{ 2 }{ Cl }_{ 6 }$

• 2)

At the home of Mr.Kumar, Dalda ghee is generally used. He is suffering from high blood pressure and diabetes. Mr.Sharma, a friend of Mr.Kumar has advised him to change from ghee to vegetable oil like mustard oil.
Dihydrogen (H2) is used in the manufacture of vanaspati ghee by hydrogenation of polyunsaturated vegetable oils using nickel as a catalyst.
Vegetable oil $\xrightarrow [ { H }_{ 2 } ]{ Ni }$ vanaspati ghee
Should we use vegetable oils for cooking? why?

• 3)

In India, there is the shortage of drinking water. Thus, projects like rainwater harvesting are used by Green Park Association to increase the amount of underground water. Rainwater is the almost pure form of water after the heavy shower as it is, in fact, the distilled water. The first shower contains dissolved gases from the atmosphere. Being a good solvent, when it flows on the surface of the earth, it dissolves many salts in the form of hydrogen carbonate, chloride and sulphate in water which make it hard Give the values possessed by the office bearer of Green Park Association?

• 4)

Scientist of UK has designed the cars, working on hydrogen fuel cells instead of petrol engines. Here hydrogen is used as sources of electrical energy i.e. a reaction of hydrogen and oxygen is used to generate electrical energy. It has many advantages over the conventional fossil fuels and electric power generation.
Give two advantages of hydrogen over fossil fuels?

• 5)

Scientist of UK has designed the cars, working on hydrogen fuel cells instead of petrol engines. Here hydrogen is used as sources of electrical energy i.e. a reaction of hydrogen and oxygen is used to generate electrical energy. It has many advantages over the conventional fossil fuels and electric power generation.
What are the values possessed by scientists of UK?

#### CBSE 11th Chemistry - Redox Reactions Four and Five Marks Questions - by Ashutosh Saran - Gurgaon - View & Read

• 1)

Justify that the reactions
4Na(s) + O2(g) $\rightarrow$ 2Na2O(s) are redox reactions.

• 2)

Given the standard electrode potentials, K+/K = -2.93V, Ag+/Ag = 0.80V, Hg2+/Hg = 0.79V, Mg2+ / Mg = -2.37V, Cr3+/Cr = -0.74V
Arrange these metals in their increasing order of reducing power.

• 3)

Identify the oxidant and reductant in each of the following reactions.
Zn(s) + 2H+(aq) $\rightarrow$ pb(s) + CO(g)

• 4)

Predict whether the following cell does exist or not?
Zn|Zn2+(1M)||Cd2+(1M)|Cd
Given,
$\left[ { E }_{ Zn,{ Zn }^{ 2+ } }^{ 0 }=0.76V \ and \ { E }_{ Cd,{ Cd }^{ 2+ } }^{ 0 }=0.40V \right]$

• 5)

Identify the redox reaction out of the following reactions and identify the oxidising and reducing in them.
3HCl(aq) + HNO3(aq) $\longrightarrow$ Cl2(g) +NOCl(g) + 2H2O(l)

#### 11th Standard CBSE Chemistry - Equilibrium Four and Five Marks Questions - by Ashutosh Saran - Gurgaon - View & Read

• 1)

Which of the following reactions involve homogeneous equilibrium and which ones involve heterogeneous equilibrium?
$2{ NH }_{ 2 }(g)\rightleftharpoons { N }_{ 2 }(g)+3{ H }_{ 2 }(g)$

• 2)

Which of the following reactions involve homogeneous equilibrium and which ones involve heterogeneous equilibrium?
$2Cu({ NO }_{ 3 })_{ 2 }\left( s \right) \rightleftharpoons 2Cuo(s)+4{ NO }_{ 2 }(g)+{ O }_{ 2 }(g)$

• 3)

For the equilibrium, $2NOCl\left( g \right) \rightleftharpoons 2NO\left( g \right) +{ Cl }_{ 2 }\left( g \right)$ the value of the equilibrium constant, ${ K }_{ c }$ is $3.17\times { 10 }^{ -6 }$ at 1069 K.
Calculate the ${ K }_{ p }$ for the reaction at this temperature?

• 4)

Classify the following species into Lewis acids and Lewis bases and show how these act as BCl3

• 5)

K1 and K2 for dissociation of H2S are 4 x 10-7 and 1 x 10-5. Calculate sulphide ion concentration in 0.1M H2S Solution.

#### 11th Standard CBSE Chemistry - Chemical Bonding and Molecular Structure Four and Five Marks Questions - by Ashutosh Saran - Gurgaon - View & Read

• 1)

Give the geometry of (CH3)3N and [(CH3)3Si]3N state if they are isostructural?

• 2)

One day when Ravi was passing by his laboratory and felt some suffocating odour. He saw his laboratory attendant was preparing some chemical, named as ammonia. Suddenly, he saw that some chemical had fallen at the hand of the attendant. He run at once and take some highly diluted HCl and apply at the burned place.By this the attendent got relief.
Can you predict and draw the structures of these compound.Also mark the central atom and find out the bond pairs and lone pairs.

• 3)

Rahul, a brilliant science student, was very keen to do experiments and get knowledge from them. One day he took some sugar and salt separately and added some acid of sulfur (which is generally used for toilet cleaning) and notice the changes. He got confused as he expected that the reaction of salt should be faster. Next day he asked about his experiment to his science teacher, who clarity the reason for the result he got. He got satisfied.
Draw the electron dot structure of acid of sulphur and salt.

• 4)

Write the resonance structures for SO3, NO2 and NO-3

• 5)

Explain with the help of suitable example polar covalent bond.

#### 11th Standard CBSE Chemistry - State of Matter Four and Five Marks Questions - by Ashutosh Saran - Gurgaon - View & Read

• 1)

On a ship sailing in Pacific ocean where temperature is $23.4^{ \circ }C$ , a balloon is filled with 2L air. What will be the volume of the balloon when the ship reaches Indian ocean, where temperature is  $26.1^{ \circ }C$ ?

• 2)

An iron cylinder contains helium at a pressure of 250 KPa at 300 K. The cylinder can withstand a pressure of $1\times { 10 }^{ 6 }Pa$ . The room in which cylinder is placed catches fire. Predict whether the cylinder will blow up before it melts or not (mp of the cylinder = 1800 K).

• 3)

Gases possess characteristic critical temperature which depends upon the magnitude of intermolecular forces between the gas particles. The critical temperature of ammonia and carbon dioxide are 405.5 K and 304.10 K respectively. Which of these gases will liquify first when you start cooling from 500 K to their critical temperature?

• 4)

Rainy season brings lots of happiness as well as lots of diseases also.Malaria, dysentery, jaundice are common diseases that occurred in this season.Children usually get affected by these diseases.Renu's teacher advised the class to drink boiled water.She also explained to test jaundice by doing a simple test based on the property of surface tension.She told them to take the urine sample in a glass and sprinkle the sulphur powder over it.If it floats, the test is negative but if it sinks, it is positive.After reading the above paragraph, answer the following questions.
What is the reason that sulphur powder floats if the test is negative but it sinks if it is positive?

• 5)

Rainy season brings lots of happiness as well as lots of diseases also.Malaria, dysentery, jaundice are common diseases that occurred in this season.Children usually get affected by these diseases.Renu's teacher advised the class to drink boiled water.She also explained to test jaundice by doing a simple test based on the property of surface tension.She told them to take the urine sample in a glass and sprinkle the sulphur powder over it.If it floats, the test is negative but if it sinks, it is positive.After reading the above paragraph, answer the following questions.
What values are expressed in the above paragraph.

#### 11th Standard CBSE Chemistry - Thermodynamics Four and Five Marks Questions - by Ashutosh Saran - Gurgaon - View & Read

• 1)

Calculate ${ \triangle }G^{ \ominus }$for the reaction
4NH3(g) + 5O2(g)$\longrightarrow$ 4NO(g) + 6H2O(l)
given that ${ \triangle }G^{ \ominus }$ for the formation of NH(g), NO(g) AND H2O (l) are - 16.8 KJ mol-1 +86.7 KJ mol-1 and -237.2KJ mol-1 respectively. predict feaibility of reaction under the conditions.

• 2)

Determine whether or not it is possible for sodium to reduce aluminium oxide to aluminium at 298 K.
$\triangle _{ f }G^{ \ominus } \ { Al }_{ 2 }{ O }_{ 3 }(s)=-1582 \ KJ \ { mol }^{ -1 };\triangle _{ f }G^{ \ominus }Na_{ 2 }O(s)=-377 \ KJ \ { mol }^{ -1 }$

• 3)

Calculate $\triangle _{ r }G^{ \ominus }$ for conversion of oxygen to ozone, 3/2 O2(g) $\rightarrow$ O3(g) at 298 Kp. If Kpfor this conversion is 2.47 x 10-29.

• 4)

Define the following:
(i) First law of thermodynamics.
(ii) Standard enthalpy of formation

#### 11th Standard CBSE Chemistry - The s-Block Elements Five Mark Model Question Paper - by Amit Pandya - Varanasi - View & Read

• 1)

Name the groups which constitute s-block elements.

• 2)

Why is the density of potassium less than sodium ?

• 3)

What happens when K burns in air ? Give chemical equation.

• 4)

Starting with sodium chloride how would you proceed to prepare? sodium hydroxide.

• 5)

Starting with sodium chloride how would you proceed to prepare? Sodium peroxide.

#### 11th CBSE Chemistry - Hydrogen Five Mark Model Question Paper - by Amit Pandya - Varanasi - View & Read

• 1)

What do you expect the nature of hydrides is, if formed by elements of atomic numbers 15, 19, 23, 44 with dry dilhydrogen? Compare their behaviour towards water.

• 2)

How would you prepare dihydrogen from a substance other than water?

• 3)

What mass of hydrogen peroxide will be present in 2L of a 5M solution?

• 4)

Calculate the mass of oxygen which will be liberated by the decomposition of 200mL of this solution.

• 5)

Complete the following chemical reactions and classify the above into (a) hydrolysis,(b) redox and (c) hydration reactions.
$PbS(s)+{ 4 }H_{ 2 }{ O }_{ 2 }(aq)\rightarrow$

#### CBSE 11th Standard Chemistry - Redox Reactions Five Mark Model Questions - by Amit Pandya - Varanasi - View & Read

• 1)

Justify that the following reaction are redox reaction
$CuO(s)+{ H }_{ 2 }(g)\rightarrow Cu(s)+{ H }_{ 2 }O(g)$

• 2)

Justify that the following reaction are redox reaction
$4BCl_{ 3 }(g)+3LiAl{ H }_{ 4 }(s)\longrightarrow 2{ B }_{ 2 }{ H }_{ 6 }(g)+3LiCl(s)+3AlC{ l }_{ 3 }(s)$

• 3)

Justify that the following reaction are redox reaction
$2k(s)+{ F }_{ 2 }(g)\longrightarrow 2K^{ + }{ F }^{ - }(s)$

• 4)

Justify that the following reaction are redox reaction
$4N{ H }_{ 3 }(g)+5{ O }_{ 2 }(g)\longrightarrow 4NO(g)+6H_{ 2 }O(g)$

• 5)

Using electron transfer concept, identify the oxidant and reductant in the redox reaction.
Zn(s) +2H+(aq)$\rightarrow$ Zn2+(aq) +H2(g)

#### 11th CBSE Chemistry - Equilibrium Five Mark Model Questions - by Amit Pandya - Varanasi - View & Read

• 1)

Calculate degree of hydrolysis,

• 2)

Calculate the pH of a buffer which is 0.1 M in acetic acid and 0.15 M in sodium acetate. Given that the ionisation costants of acetic acid is 1.75 x 10-5. Also calculate the change in pH of the buffer if to 1L of the buffer 1 cc of 1 M NaOH are added.

• 3)

Calculate the hydrogen ion concentration in the following biological fluids whose pH are given below.
Human muscle-fluid, 6.83

• 4)

The pH of milk, black coffee, tomato juice, lemon juice and egg white are 6.8,5.0,4.2,2.2 and 7.8 respectively. Calculate the corresponding hydrogen ion concentration in each.

• 5)

On the basic of Le-Chatelier principle explain how temperature and pressure can be adjusted to increase the yield of ammonia in the following reaction.
${ N }_{ 2 }\left( g \right) +3{ H }_{ 2 }\left( g \right) \rightleftharpoons 2{ NH }_{ 3 }\left( g \right) \triangle H=192.38 \ KJ \ { mol }^{ -1 }$ What will be the effect of addition of argo to the above reaction mixture at constant volume?

#### CBSE 11th Chemistry - Classification of Elements and Periodicity in Properties Four and Five Marks Questions - by Ashutosh Saran - Gurgaon - View & Read

• 1)

The elements Z = 117 and 120 have not yet been discovered. In which family/group would you place these elements and also give the electronic configuration in each case.

• 2)

Calculate the electronegativity of carbon if EH-H = 104.2 kcal mol-1, EC-C =  83.1 kcal mol-1,EC-H = 98.8 kcal mol-1, X= 2.1.

• 3)

The first $({ \triangle }_{ i }{ H }_{ 1 })$ and the second $({ \triangle }_{ i }{ H }_{ 2 })$ ionization enthalpies (in kJ mol-1) and the $({ \triangle }_{ eg }H)$ electron gain enthalpy (in kJ mol-1 ) of a few elements are given below

 Elements ${ \triangle }_{ i }{ H }_{ 1 }$ ${ \triangle }_{ i }{ H }_{ 2 }$ ${ \triangle }_{ eg }H$ I 520 7300 -60 II 419 3051 -48 III 1681 3374 -328 IV 1008 1846 -295 V 2372 5251 +48 VI 738 1451 -40

Which of the above elements is likely to be
(i)   the least reactive element?
(ii)  the most reactive metal?
(iii)  the most reactive non-metal?
(iv)  the least reactive non-metal?
(v)   the metal which can form a stable binary halide of the formula MX2(X = halogen)?
(vi)  the metal which can form a predominantly stable covalent halide of the formula MX (X = halogen)?

• 4)

Arrange the following in decreasing order of their van der Waals' radii CI, H, O, N.

• 5)

Chemical reactivity of elements is highest at the two extremes of a period and is lowest in the center. Highly reactive elements do not occur in nature in free state, they usually occur in nature in free state, they usually occur in combined state. Some students are highly aggressive and keep on fighting with each other like highly reactive elements. Some students are sober and help each other and do not fight.
(i) Elements of which group are most reactive?
(ii) Which group elements are least reactive and why?
(iii) What are the harmful effects of being aggressive?
(iv) What values are possessed by sober people?
(v) Which kind of people pick up fight, while driving on the road in case of accidents? What are its consequences? What should we do?

#### 11th Standard CBSE Chemistry - Structure of Atom Four and Five Marks Questions - by Ashutosh Saran - Gurgaon - View & Read

• 1)

Which state of the triple ionised beryllium $(Be^{ 3+ })$ has the same orbit radius at that of the ground state of hydrogen atom?

• 2)

The wavelength range of the visible spectrum extends from violet nm). Express these wavelengths in frequencies (Hz). (nm = 9 m).

• 3)

The number of electrons, protons and neutrons in a species are equal to 18, 16 and 16 respectively. assign the proper symbol o the species.

• 4)

The threshold frequency (vo ) for a metal is $7.0\times { 10 }^{ 14 }{ s }^{ -1 }$ . Calculate the kinetic energy of an electron emitted when radiation of frequency (v) = 1.0 x 1015 s-1 hits the metal.

• 5)

A golf ball has a mass of 40g and a speed of 25 m/s. If the speed can be measured within accuracy of 2%, calculate the uncertainty in the position.

#### 11th Standard CBSE Chemistry - Some Basic Concept of Chemistry Four Marks and Five Marks Questions - by Ashutosh Saran - Gurgaon - View & Read

• 1)

Convert the following into basic units
25365 mg.

• 2)

At what temperature will both the Celsius and Fahrenheit scales read the same value ?

• 3)

A measured temperature on Fahrenheit scale is 200o F. What will this reading be on Celsius scale?

• 4)

Express the following in the scientific notation
(4.56 x 103 + 2.62 x 102)

• 5)

Express the following in the scientific notation
(9.87 x 10-3 - 2.26 x 10-4)

#### 11th Standard CBSE Chemistry - Environmental Chemistry Three Marks Questions - by Ashutosh Saran - Gurgaon - View & Read

• 1)

What are pesticides and herbicides? Explain giving examples.

• 2)

How is the temperature effected as we go up the earth's surface? Explain

• 3)

What do you mean by ozone hole? What are its consequences?

• 4)

Sonu and Nilesh were friends. In winters, one day when they were going to school at 10:00 am Sonu felt irritation in his eyes and throat. He was also unable to breath.
Nilesh immediately took him to a doctor. Doctor gave him the proper remdy. When he became well, Nilesh asked reason for this Doctor answered him satisfactorily.
(i) Can you guess what reason was given by the doctor for the illness of Sonu.
(ii) Why such kind of polluting atmospheric change occurs?
(iii) What should be done to prevent the formation of smog?
(iv) What values are possessed by Nilesh?

• 5)

Explain the tropospheric pollution in 100 words?

#### CBSE 11th Chemistry - Hydrocarbons Three Marks Questions - by Ashutosh Saran - Gurgaon - View & Read

• 1)

How do you account for theformation of ethane during chlorination of methane?

• 2)

For the following compounds, write structural formulas and IUPAC names for all possible isomers having the number of double or triple bond as indicated:
(a) C4H8 (one double bond)
(b) C5H8 (one triple bond)

• 3)

An alkene 'A' contains three C-C, eight C-H, $\sigma$-bonds, and one C-C $\pi$-bond. 'A' on ozonolysis gives two moles of an aldehyde of molar mass 44 u. Write the IUPAC name or 'A'.

• 4)

Why is benzene extra-ordinarily stable though it contains three double bonds?

• 5)

What are the necessary conditions for any system to be aromatic?

#### CBSE 11th Chemistry - Organic Chemistry: Some Basic Principles and Techniques Three Marks Questions - by Ashutosh Saran - Gurgaon - View & Read

• 1)

Write down the formula of the first four members of each homologous series beginning with the following compounds.
${ CH }_{ 3 }CO{ CH }_{ 3 }$

• 2)

Write down the formula of the first four members of each homologous series beginning with the following compounds.
${ CH }_{ 3 }OH$

• 3)

Write down the formula of the first four members of each homologous series beginning with the following compounds.
$HC\equiv CH$

#### CBSE 11th Chemistry - The p-block Elements Three Marks Questions - by Ashutosh Saran - Gurgaon - View & Read

• 1)

A certain salt X, gives the results Borax swells up to a glassy mass on strong heating.
Is swells up to a glassy material Y on strong heating

• 2)

Explain the following.
Aluminium forms [AlF6]3- ion but boron does not form [BF6]3-ion.

• 3)

Account for CO is poisonous.

• 4)

Account for CO2 is used in refrigeration.

• 5)

What are electron deficient compounds? Are BCl3 and SiCl4 electron deficient species? Explain.

#### CBSE 11th Chemistry - The s-Block Elements Three Marks Questions - by Ashutosh Saran - Gurgaon - View & Read

• 1)

Compare the alkali metals and alkaline earth metals with respect to basicity of oxides

• 2)

Present a comparative account of the alkali and akaline earth metals with respect to the following characteristics.
Nature of oxides and their solubility in water

• 3)

Present a comparative account of the alkali and akaline earth metals with respect to the following characteristics.
solubility of oxosalt

• 4)

Explain the Aluminium utensils should not be kept in water overnight.

#### CBSE 11th Chemistry - Hydrogen Three Marks Questions - by Ashutosh Saran - Gurgaon - View & Read

• 1)

If 1kg of a hard water sample contains 12 mg of CaCl2 and 12mg of MgCl2, then what will be the total hardness in terms of CaCO3 Per 106 parts by mass of water sample.

• 2)

Write equations for the reactions
Peroxydisulphuric acid is hydrolysed.

• 3)

Calculate the volume strength of a 3% solution of ${ H }_{ 2 }O_{ 2 }$

• 4)

What are the advantages in using hydrogen as a fuel?

• 5)

Why is hydrated barium peroxide used in the preparation of hydrogen peroxide instead of anhydrous barium peroxide?

#### 11th Standard CBSE Chemistry - Redox Reactions Three Marks Questions - by Ashutosh Saran - Gurgaon - View & Read

• 1)

Suggest a list of the substance where carbon can exhibit oxidation states from -4 to +4 and nitrogen from -3 to +5

• 2)

Write formulae for the compounds.
Mercury (II) chloride

• 3)

Write formulae for the compounds.
Chromium (III) oxide

• 4)

Whenever a reaction between an oxidising agent and a reducing agent is carried out a, compound of lower oxidation state is formed if the reducing agent is in excess and a compound of higher oxidation state is formed if the oxidation agent is in excess. Justofy this statement givng three illustrations.

• 5)

Identify the type of redox reaction taking place in the following
$2\overset { +1 }{ K } \overset { 5 }{ CI } \overset { -2 }{ O } _{ 3 }(s)\longrightarrow 2\overset { -1 }{ K } \overset { -1 }{ CI } (s)+3\overset { 0 }{ O } _{ 2 }(g)$

#### 11th Standard CBSE Chemistry - Equilibrium Three Marks Questions - by Ashutosh Saran - Gurgaon - View & Read

• 1)

What is the minimum volume of water required to dissolved 1g of calcium sulphate at 298 K? (For calcium sulphate, Ksp is 9.1 x 10-6).

• 2)

The ionisation constant of acetic acid is ED 1.74 x 10-5. Calculate the degree of dissociation of acetic acid in its 0.05 M solution. Calculate the concentration of acetate ion in the solution and its pH.

• 3)

An equilibrium mixture at 300K contains N2 O4 and NO2 at .28 and 1.1 atm pressure respectively. If the volume of the container is doubled, calculate the new equilibrium pressure of two gases.

• 4)

The ionisation constant of dimethylamine is 5.4 x 10-4. Calculate its degree of ionisation in its 0.02 M solution. What percentage of dimethylamine is ionised if the solution is also 0.1 M in NaOH?

• 5)

At 473K, equilibrium constant Kc for decomposition of phosphorus pentachloride Pcl5 is $8.3\times { 10 }^{ -3 }$ . If decomposition is depicted as,
${ PCl }_{ 5 }(g)\leftrightharpoons { PCl }_{ 3 }(g)+{ Cl }_{ 2 }(g);$
$\Delta H°=124.0 \ { kJmol }^{ -1 }$

What would be the effect on ${ K }_{ c }$ if (a) more PCl5   is added (b) pressure is increased (c) the temperatured in increased ?

#### 11th Standard CBSE Chemistry - Thermodynamics Three Marks Questions - by Ashutosh Saran - Gurgaon - View & Read

• 1)

A man takes a diet equivalent to 10000 kJ per day and does work, in expending his energy in all forms equivalent to 12500 kJ per day. What is change in internal energy per day?If the energy lost was stored as sucrose (1632 kJ pre 100g), how many days should it take to lose 2kg of his weight?(Ignore water loss)

• 2)

The enthalpy of vaporization of liquid diethyl ether (C2H5)20 is 26.0 KJ mol-1 at its boiling point (35.0oC). Calculate $\triangle$So for the conversion of Liquid to vapour and

• 3)

Calculate the standard Gibbs energy change for the formation of propane at 298 K.
3 C (graphite) + 4H2(g) → C3H8 (g)
$\triangle _{ f }{ H }^{ o }for\quad propane,{ C }_{ 3 }{ H }_{ 8 }(g)=270.2J{ K }^{ -1 }{ mol }^{ -1 }$
${ S }_{ m }^{ o }C(graphite)=5.70J{ K }^{ -1 }{ mol }^{ -1 }$
$and \ { S }_{ m }^{ 0 }{ H }_{ 2 }(g)=130.7J{ K }^{ -1 }{ mol }^{ -1 }$

• 4)

The molar heat of formation of NH4NO3 (s) is -367.54 kJ and those of N2 O(g) and H2O(i) are + 81.46 kJ and -258.78 kJ respectively at 25oC and 1.0 atmospheric pressure. Calculate $\Delta$H and $\Delta$U for the reaction.

• 5)

Justify the following statements.
Reaction with $\triangle$G< 0 always have an equilibrium constant greater than 1.

#### 11th Standard CBSE Chemistry - State of Matter Five Mark Question Paper - by Amit Pandya - Varanasi - View & Read

• 1)

Explain
The boiling point of a liquid rises on increasing pressure.

• 2)

Explain
The level of mercury in a capillary tube is lower than the level outside when a capillary tube inserted in the mercury.

• 3)

Tea or coffee is sipped from a saucer when it is quite hot.

• 4)

Calculate the total and average kinetic energy of 32 g methane molecules at 27oC(R = 8.314 JK-1 mol-1 )

• 5)

Nitrogen molecule(N2 )has radius of about 0.2 nm. Assuming that nitrogen molecule is spherical in shape, calculate volume of a single molecule of N2

#### 11th Standard CBSE Chemistry - Thermodynamics Five Mark Question Paper - by Amit Pandya - Varanasi - View & Read

• 1)

An athlete is given 100g of glucose of energy equivalent to 1560 kJ. He utilises 50% of this gained energy in the event.In order to avoid storage of energy in the body, calculate the weight of water that would need to perspire.The enthalpy of vaporisation of water is 44 kJ mol-1.

• 2)

When 20.0 g of ammonium nitrate (NH4NO3) is dissolved in 125 g of water in a coffee cup calorimeter. (Treat heat capacity of water as the heat capacity of the calorimeter and its contents).

• 3)

A chemist while studying the properties of gaseous CCl2, a chlorofluorocarbon refrigerant, cooled a 1.25 g sample at a constant atmospheric pressure of 1.0 atm from 320 K to 293 K. During cooling, the sample volume decreased from 274 to 248 mL. Calculate $\Delta$H and $\Delta$U for the chlorofluorocarbon for this process. For CCl2F2, Cp = 80.7 J/(mol K).

• 4)

A cylinder of gas supplied by a company is assumed to contain 14kg of butane.If a normal family requires 20000kj of energy per day for cooking, how long will the cylinder last?

• 5)

If the air supplied to the burner is insufficient, a portion of gas escapes without combustion. Assuming that 25% of the gas is wasted due to this inefficiency, how long will the cylinder last (Heat of combustion of butane = 2658 kJ/mol)?

#### 11th Standard CBSE Chemistry - Chemical Bonding and Molecular Structure Five Mark Question Paper - by Amit Pandya - Varanasi - View & Read

• 1)

Arrange the following in increasing order of ionic character  and also give the reason.
NaCl, CaCl2, MgCl2, MgO.

#### 11th Standard CBSE Chemistry - Classification of Elements and Periodicity in Properties Five Mark Question Paper - by Amit Pandya - Varanasi - View & Read

• 1)

Use the periodic table to answer the following questions.
Identify an element with five electrons in the outer subshell.

• 2)

Which elements have the following electronic configuration? (Use only the periodic table.)
1s2, 2s2, 2p5

• 3)

Which elements have the following electronic configuration? (Use only the periodic table.)
[Xe] 6s2

• 4)

Which elements have the following electronic configuration? (Use only the periodic table.)
[Ar] 4s1, 3d10 (exception to rules)

• 5)

In p-block elements form acidic, basic and amphoteric oxides. Explain each property by giving two examples and also write the reactions of these oxides with water.

#### 11th CBSE Chemistry - Structure of Atom Five Mark Question Paper - by Amit Pandya - Varanasi - View & Read

• 1)

Show that the circumference of the Bohr orbit for the hydrogen atom is an integral multiple of the de-Broglie wavelength associated with the electron revolving around the orbit.

• 2)

Calculate the energy required for the process
$He^{ + }\left( g \right) \longrightarrow { He }^{ 2+ }\left( g \right) +{ e }^{ - }$
The ionisation energy for the atom in the ground state is $2.18\times { 10 }^{ -18 }J{ \ atom }^{ -1 }$.

• 3)

A photon of wavelength 4 x 10-7 m strikes on the metal surface, the work function of the metal being 2.13 eV. Calculate the velocity of the photoelectron (1 eV = 1.6020 x 10-19 J).

• 4)

A beam of helium of atoms move with a velocity of $2.0\times { 10 }^{ 3 }{ ms }^{ -1 }$ Find the wavelength of the particle constituting the beam. (h = 6.626 $\times$10-34 Js).

• 5)

List the quantum number (ml and l) of electrons for 3d - orbital.
Notes:
l has the value 0 to (n - 1)
m has the value -l to l
The value of l never be equal to n or greater than it.

#### 11th CBSE Chemistry - Some Basic Concept of Chemistry Five Mark Question Paper - by Amit Pandya - Varanasi - View & Read

• 1)

How many atoms of He are present in 52 $\mu$ of He?

• 2)

A lady purchases a ring from a jeweller with diamonds embedded into it. The jeweller tells that total diamond used in the ring is five carat. How much weight he should subtract from the weight of the ring to get the weight of gold?

• 3)

Round up the following up to three significant figures.
34.216

• 4)

Copper sulphate crystals contain 25.45% Cu and 36.07% H2O. If the law of constant proportions is true then calculate the weight of Cu requires to obtain 40g of crystalline CuSo4.

#### CBSE 11th Chemistry - State of Matter Three Marks Questions - by Ashutosh Saran - Gurgaon - View & Read

• 1)

A gas is enclosed in the room. The temperature, pressure, density, and the number of moles respectively are t $^{o}$C, p atm, g cm-3 and n moles. What will be the values of pressure, temperature, density, and the number of moles in each compartment if the walls between the two compartments (say 1 and 2) are removed?

• 2)

A 2 L flask contains 1.6g of methane and 0.5 g of hydrogen at 27oC. Calculate the partial pressure of each gas in the mixture and also calculate the total pressure.

• 3)

0.64 g of an oxide of sulphur occupies 0.224 L at 2 bars and 273oC. Identify the compound.Also, find out the mass of one molecular of the gas.

• 4)

The compression factor(compressibility factor) for one mole of a van der Waals gas at 0oC and 100 atm pressure is found to be 0.5. Assuming that the volume of a gas molecule is negligible, calculate the van der Walas' constant a.

#### 11th Standard CBSE Chemistry - Chemical Bonding and Molecular Structure Three Marks Questions - by Ashutosh Saran - Gurgaon - View & Read

• 1)

Explain the following on the basis of valence bond theory. CCl4 and SiCl4 are tetrahedral.

• 2)

Explain the following on the basis of valence bond theory. The HSH bond angle is H2S is closer to 900 than HOH bond angle in H2O.

• 3)

On the basis of molecular orbital theory what is similarly between ${ F }_{ 2 },{ O }_{ 2 }^{ 2- }$

• 4)

On the basis of molecular orbital theory what is similarly between $CO,{ N }_{ 2 },{ NO }^{ + }$

#### 11th Standard CBSE Chemistry Unit 3 Classification of Elements and Periodicity in Properties Three Marks Questions - by Ashutosh Saran - Gurgaon - View & Read

• 1)

Give the name and atomic number of the inert gas atom in which the total number of numbers of d-electrons is equal to the difference in numbers of total p and s electrons.

• 2)

Can an element with atomic number 126, if discovered, be accommodated in the present set up of the long form of periodic table?

• 3)

First member of each group of representative elements  ( i.e. sand p-block elements ) shows anomalous behaviour. Illustrate with two examples.

• 4)

Arrange the following as stated. 'Decreasing order of electropositive character of Cu, Fe Mg'

#### 11th Standard CBSE Chemistry Unit 2 Structure of Atom Three Marks Questions - by Ashutosh Saran - Gurgaon - View & Read

• 1)

Which of the following are isoelectronic species, i.e those having the same number of electrons?
Na+,K+,Mg2+,Ca2+,S2-,Ar

• 2)

Write the complete symbol for the atom with the given number (Z) and atomic mass (A). Z = 17, A  = 35

• 3)

Correct the following electronics configuration of the elements in the ground state.
${ 1s }^{ 2 }2s^{ 2 },{ 2p }^{ 6 },3s^{ 2 },{ 3p }^{ 6 },3d^{ 5 }$

• 4)

Correct the following electronics configuration of the elements in the ground state.
${ 1s }^{ 2 }2s^{ 2 },{ 2p }^{ 6 },3s^{ 2 },{ 3p }^{ 6 },3d^{ 4 },4s^{ 2 }$

• 5)

Which of the following sets of orbitals are degenerate and why? 2px, 2py and 2pz in C-atom.

#### 11th Standard CBSE Chemistry - Some Basic Concept of Chemistry Three Marks Questions - by Ashutosh Saran - Gurgaon - View & Read

• 1)

How many amny significant figures present in the following? "5005"

• 2)

How many amny significant figures present in the following? "126000"

• 3)

To account for the atomic mass of nitrogen as 14.0067,$\mu$ what should be the ratio of and atoms ${ 15 }_{ N }$${ 14 }_{ N }$ in natural nitrogen? (atomic mass of ${ 14 }_{ N }$ = 14.00307 $\mu$ and ${ 15 }_{ N }$ = 15.001$\mu$)

• 4)

A compound contains 4.07% hydrogen, 24.27% carbon and 71.65 % chlorine. Its molar mass is 98.96 g. Determine its empirical and molecular formulae.

• 5)

Convert the following into meter. '40 Em (thickness of milky way galaxy)'

#### CBSE 11th Chemistry - Environmental Chemistry Two Marks Questions - by Ashutosh Saran - Gurgaon - View & Read

• 1)

What could be the harmful effects of improper management of industrial and domestic solid waste in a city?

• 2)

For dry cleaning in the place of tetrachloroethene, liquefied carbon dioxide with suitable detergent is an alternative solvent. What type of harm to the environment will be prevented by stopping use of tetrachloroethene? Will use of liquefied carbon dioxide with detergent be completely safe from the point of view of pollution. Explain.

• 3)

What do you mean by primary and secondary pollutants of the air?

• 4)

Which zone is known as ozonosphere?

• 5)

Which main gases is responsible for damage in ozone layer?

#### 11th Standard CBSE Chemistry - Hydrocarbons Two Marks Questions - by Ashutosh Saran - Gurgaon - View & Read

• 1)

Rotation around carbon-carbon single bond of ethane is not completely free. Justify the statement.

• 2)

On converting benzene to toluene, state whether there will be a rise or fall in the melting point.

• 3)

Why do you alkenes prefer to undergo electrophilic addition reaction while arenes prefer electrophilic substitution reactions? Explain.

• 4)

Draw the cis- and trans-structures for hex-2-ene. Which iosmer will have higher b.p. and why?

• 5)

What effect does branching of an alkane chain has on its boiling point?

#### 11th Standard CBSE Chemistry - Organic Chemistry: Some Basic Principles and Techniques Two Marks Questions - by Ashutosh Saran - Gurgaon - View & Read

• 1)

Give the common name of methanol.

• 2)

How many $\sigma$ and  $\pi$ bonds are present in each of the following molecules?
$CH_{ 3 }-CH=CH-CH_{ 2 }-C\equiv CH$

• 3)

Identify the most stable species in the following set of ions giving reasons
$\overset { - }{ C } { H }_{ 3 },\overset { - }{ C } { H }_{ 2 }CI,\overset { - }{ C } { H }CI_{ 2 },\overset { - }{ C } CI_{ 3 }$

• 4)

Which bond is more polar in the following pair of molecules?
H3C - H or H3C - Br

• 5)

What is meant by delocalization?

#### 11th Standard CBSE Chemistry - The p-block Elements Two Marks Questions - by Ashutosh Saran - Gurgaon - View & Read

• 1)

Discuss the pattern of variation in the oxidation states of B to TI

• 2)

How does electron deficient compound BF3 achieve electronic saturation , i.e fully ooccupied outer electron shells?

• 3)

Give one chemical reaction to show that Tin(II) chloride is a reducing agent.

• 4)

Give reasons.
Conc.HNO3 can be transported in aluminium container.

• 5)

Why does lime water turn milky when CO2  is passed through it.

#### CBSE 11th Chemistry - The s-Block Elements Two Marks Questions - by Ashutosh Saran - Gurgaon - View & Read

• 1)

A white solid X is a compound of alkali metal. A piece of red litmus paper turns white when it is dipped into a freshly made aqueous solution of the white solid. Identify the white solid X.

• 2)

Write the Lewis structure of O2- ion and find out oxidation state of each oxygen atom? What is the average oxidation state of oxygen in this ion?

• 3)

Explain why can alkali and alkaline earth metals not be obtained by chemical reduction methods?

• 4)

What happens when magnesium reacts with SOgas ?

• 5)

When alkali metals dissolves in liquid ammonia, the solution can acquire different colours.Explain the reason for. this type of colour change.

#### CBSE 11th Chemistry - Hydrogen Two Marks Questions - by Ashutosh Saran - Gurgaon - View & Read

• 1)

${ H }_{ 2 }{ O }_{ 2 }$ is a better oxidising agent than water as discussed below. Explain.

• 2)

Calculate the strength of 10 volume solution of hydrogen peroxide.

• 3)

Explain the correct context in which the following terms are used diprotium.

• 4)

Would you expect the hydrides of N, O and F to have lower boiling points than the hydrides of their subsequent group members? Give reasons.

• 5)

How do you expect the metallic hydrides to be useful for hydrogen storage? Explain

#### 11th Standard CBSE Chemistry - Redox Reactions Two Marks Questions - by Ashutosh Saran - Gurgaon - View & Read

• 1)

Balance the following equations in basic medium by ion electron and oxidation number methods and identify the oxidising agent and the reducing agent
$CI_{ 2 }O_{ 7 }(g)+H_{ 2 }O_{ 2 }(aq)\longrightarrow CIO_{ 2 }^{ - }(aq)+O_{ 2 }(g)$

• 2)

A solution of silver nitrate was stirred with iron rod.Will it cause any change in the concentration of silver and nitrate ions?

• 3)

How many millimoles of potassium dichromate is required to oxidise 24mL of 0.5 M Mohr's salt solution in acidic medium?

• 4)

Two half cells are AI3+ (aq) /AI and Mg2+ (aq)/Mg.The reduction potentials of these half-cells are -1.66 V and -2.36 V respectively. Calculate the cell potential. Write the cell reaction also.

• 5)

Assign oxidation number to the underlined elements in each of the following species - K2MnO4

#### 11th Standard CBSE Chemistry - Equilibrium Two Marks Questions - by Ashutosh Saran - Gurgaon - View & Read

• 1)

How much volume of 0.1 M HAc should be added to 50 mL of 0.2 M HAc solution if we want to prepare a buffer solution of pH 4.91. Given pKa for acetic acid is 4.76.

• 2)

Which of the following reactions involve homogeneous equilibrium and which involve heterogeneous equilibrium?
${ Ag }_{ 2 }O(s)+2HN{ O }_{ 3 }(aq)\rightleftharpoons 2{ Ag }NO_{ 3 }(aq)+{ H }_{ 2 }O(l)$

• 3)

Which of the following reactions involve homogeneous equilibrium and which involve heterogeneous equilibrium?
$2SO_{ 2 }(g)+O_{ 2 }(g)\rightleftharpoons 2SO_{ 3 }(g)$

• 4)

Explain why pure liquids and solids can be ignored while writing the value of equilibrium constants.

#### CBSE 11th Chemistry - Thermodynamics Two Marks Questions - by Ashutosh Saran - Gurgaon - View & Read

• 1)

The enthalpy of a vaporisation of CCI4 is 30.5 kJ mol-1. Calculate the heat required for the vaporisation of 284g of CCI4 at constant pressure (molar mass of CCI4 =154 g mol-1)

• 2)

Calculate the number of kJ of haet necessary to raise the temperature of 60.0g of aluminium from 35 $^{ \circ }$C to 55$^{ \circ }$C. Molar heat capacity of Al is 24Jmol$^{ -1 }$K$^{ -1 }$ . Molar mass of Al = 27gmol$^{ -1 }$

• 3)

18.0 g water completely vaporises at 100 oC and 1 bar pressure and the enthalpy change in the process is 40.79 KJ mol-1. What  will be the enthalpy change for vaporising two moles of water under the same conditions? What is the standard enthalpy of vaporisation for water?

• 4)

Although heat is path function but heats absorbed by the system under certain specific conditions is independent of path. what are those conditions? Explain when pressure remains constant.

#### CBSE 11th Chemistry - State of Matter Two Marks Questions - by Ashutosh Saran - Gurgaon - View & Read

• 1)

Use the information and data given below to answer the question, stronger intermolecular forces result in higher boiling point.
Strength of London forces increases with the number of electrons in the molecules. Boiling point of HF, HCI, HBr, and HI are 293 K, 189 K, 206 K and 238 K respectively.
Looking at the trend of boiling points of HCI, HBr, and HI, explain out of dipole-dipole interaction and London interaction, which one is predominant here.

• 2)

Calculate the kinetic energy of 2g of oxygen at -23oC

• 3)

The density of liquid CO2 at room temperature is 0.8 g cm-3 .how large a cartridge of liquid CO2 must be provided to inflate a life jacket of 4 L capacity at STP?

• 4)

It is desired to increase the volume of 800 mL of a gas by 20% keeping the pressure constant. To what temperature the gas must be heated if the initial temperature is 22oC?

• 5)

150 mL of a gas at NTP were taken to 20oC and 0.96 bar pressure. What is the change in volume of the gas?

#### 11th CBSE Chemistry - Chemical Bonding and Molecular Structure Two Mark Questions - by Ashutosh Saran - Gurgaon - View & Read

• 1)

Arrange the bonds in order of increasing ionic character in the molecules: LiF, K2O , N2, SO2 and ClF3 .

• 2)

Arrange the following bonds in order of increasing ionic character giving reason. N-H, F-H, C-H and O-H

• 3)

Arrange the following in order of decreasing bond angle, giving reason NO2$NO_{ 2 }^{ + }$ and $NO_{ 2 }^{ - }$

• 4)

Explain the shape of BrF5

#### CBSE 11th Chemistry Unit 3 Classification of Elements and Periodicity in Properties Two Marks Questions - by Ashutosh Saran - Gurgaon - View & Read

• 1)

Which important property did Mendeleev use to classify the elements in his periodic table and did he stick to that?

• 2)

All transition elements are d-block elements, but all d-block elements are not transition elements. Explain.

• 3)

List the factors that can influence the ionic radius of an element.

• 4)

Show by a chemical reaction with water that ${ Na }_{ 2 }O$ is a basic oxide and $Cl_{ 2 }O_{ 7 }$is an acidic oxide.

#### CBSE 11th Chemistry - Structure of Atom Two Marks Questions - by Ashutosh Saran - Gurgaon - View & Read

• 1)

Why does the charge to mass ratio of positive rays depend on the residual gas in the discharge tube? Why is the charge to mass ratio of all cathode rays are same?

• 2)

Calculate energy of one mole photons of radiation whose frequency is 5 x 1014 HZ.

• 3)

In astronomical observations, signals observed from the distant stars are generlly weak. If the photon detector receives a total of 3.15 x 10-18 J from the radiations of 600 nm, calculate the number of photons received by the detector.

• 4)

Calculate wave number of the line having frequency 5 x 1016 Hz.

• 5)

Calculate the energy of one mole of the photons of a beam of light having wavelength 25.0 $\mu$m.

#### 11th Standard CBSE Chemistry Unit 1 Some Basic Concept of Chemistry Two Mark Questions - by Ashutosh Saran - Gurgaon - View & Read

• 1)

Express the following number to three significant figures. "Sixty thousand"

• 2)

Express the following number to three significant figures. " 2.861$\times$10"

• 3)

The reactant which is entirely consumed in reaction is known as limiting reagent. In the reaction 2A + 4B $\Rightarrow$ 3C + 4D, when 5 moles of A react with 6 moles of B, then calculate the amount of C formed?

• 4)

The water level in a metric measuring cup is 0.75 L before the addition of a pebble weighing 150 g. The water level after submerging the pebble is 0.82 L. Determine the density of the pebble.

• 5)

One of the statements of Dalton's atomic theory is given below "compounds are formed when atoms of different elements combine in a fixed ratio". Which laws of chemical combination is not related to this statement?

#### CBSE 11th Chemistry Unit 14 Environmental Chemistry Book Back Questions - by Ashutosh Saran - Gurgaon - View & Read

• 1)

Why does water covered with excessive algae growth become polluted?

• 2)

In what regions of the atmosphere,the temperature increases with altitude and in which regions it decreases?

• 3)

Name three natural sources of air pollution.

• 4)

What are viable and non-viable particulates?

• 5)

What is the nature of 'London smog' and why?

#### CBSE 11th Chemistry Unit 12 Organic Chemistry: Some Basic Principles and Techniques Book Back Questions - by Ashutosh Saran - Gurgaon - View & Read

• 1)

In the organic compound CH2=CH-CH2-CH2-C$\equiv$CH, the CH-CH2 bond is formed by the interaction of a pair of hybridised orbitals:

• 2)

The following reaction is classified as:
CH3CH2I + KOH (aq) $\rightarrow$CH3CH2OH + KI

• 3)

What are primary and secondary suffixes as applied to IUPAC nomenclature?

• 4)

How many $\sigma$ and $\pi$ bonds are present in each of the following molecules
$CH_{ 2 }==C==CHCH_{ 3 }$

#### CBSE 11th Chemistry Unit 11 The p-block Elements Book Back Questions - by Ashutosh Saran - Gurgaon - View & Read

• 1)

What is the formula of kernite, an ore of boron?

• 2)

Are all the B-H bonds in diborane equivalent?

#### CBSE 11th Chemistry - The s-Block Elements Book Back Questions - by Ashutosh Saran - Gurgaon - View & Read

• 1)

Which of the alkali metal is having least melting point?

• 2)

Which one of the following alkali metals give hydrated salts?

• 3)

Which one of the following alkaline earth metal carbonates is thermally most stable

• 4)

State as to why a solution of Na2CO3 is alkaline?

• 5)

The second ionisation enthalpy of calcium is more that of first and yet calcium forms MgCI2 not MgCL. why?

#### CBSE 11th Chemistry - Hydrogen Book Back Questions - by Ashutosh Saran - Gurgaon - View & Read

• 1)

Suggest a method to show the electronegative nature of hydrogen.

• 2)

How can saline hydrides remove traces of water from organic compounds?

• 3)

Explain why beryllium forms a covalent hydride while calcium forms an iconic hydride.

• 4)

Name the isotope of hydrogen which is commonly used as a tracer in organic reactions.

• 5)

Name the constituents of water gas.

#### 11th Standard CBSE Chemistry Unit 8 Redox Reactions Book Back Questions - by Ashutosh Saran - Gurgaon - View & Read

• 1)

Does the oxidation number of an element in any molecule or any polyatomic ion represent the actual charge on it?

• 2)

The compound YBa2Cu3O7, Which shows superconductivity, has copper in x oxidation state. Assume that the rare earth element yttrium is in its usual +3 oxidation state. Predict the value of x.

#### 11th Standard CBSE Chemistry Unit 7 Equilibrium Book Back Questions - by Ashutosh Saran - Gurgaon - View & Read

• 1)

A tank is full of water. Water is coming in as well as going out at same rate. What will happen to level of water in a tank? What is name given to such a state?

• 2)

What is the expression for ${ k }_{ sp } \ of \ { Ag }_{ 2 }Cr{ 0 }_{ 4 }?$

• 3)

Under the conditions is a substance precipitated from its solution?

• 4)

pKa  value of acids A,B,C,D are 1.5, 3.5, 2.0 and 5.0.Which of them is strongest acid?

#### 11th Standard CBSE Chemistry Unit 6 Thermodynamics Book Back Questions - by Ashutosh Saran - Gurgaon - View & Read

• 1)

A thermodynamic state function is a quantity

• 2)

A reaction, A + B $\rightarrow$  C + D + q is found to have a positive entropy change. The reaction will be

• 3)

As per the available data:

• 4)

In the equation, ${ N }_{ 2 }(g)+3{ H }_{ 2 }(g)\rightleftharpoons 2N{ H }_{ 3 }(g)$ what would be the sign of work done?

• 5)

At 1 atm will the ${ \triangle }_{ f }{ H }^{ \circ }$ be zero for Cl2(g) and Br2 (g)? Explain.

#### 11th Standard CBSE Chemistry Unit 5 State of Matter Book Back Questions - by Ashutosh Saran - Gurgaon - View & Read

• 1)

One of the assumptions of kinetic theory of gases states that "there is no force of attraction between the molecules of a gas "How far is this statement correct?Is it possible to liquefy an ideal gas? Explain.

• 2)

A gas that follows Boyle's law, Charle's law and Avogadro's law is called an ideal gas.Under what condition a real gas would behave ideally?

• 3)

Explain why temperature of a boiling liquid remains constant?

• 4)

Explain the physical significance of van derWaals' parameters.

• 5)

What would have happened to the gas if the molecular collision were not elastic?

#### 11th Standard CBSE Chemistry Unit 4 Chemical Bonding and Molecular Structure Book Back Questions - by Ashutosh Saran - Gurgaon - View & Read

• 1)

Why axial bonds of PCI5 are longer than equatorial bonds?

#### 11th Standard CBSE Chemistry Unit 3 Classification of Elements and Periodicity in Properties Book Back Questions - by Ashutosh Saran - Gurgaon - View & Read

• 1)

Why were the names eka-aluminium and eka-silicon given to gallium and germanium by Mendeleev?

• 2)

Why do elements in the same group have similar physical and chemical properties?

• 3)

A boy has reported the radii of Cu,Cu+ and Cu2+ as 0.096 nm,0.122 nm and 0.072 nm respectively.However, it has been noticed that he interchanged the values by mistake. Assign the correct values to different species.

• 4)

Four elements have the following first ionisation enthalpies ( in kJ mol-1); 869, 941, 1191 and 1142. The elements, in random order, are Se, Br, Te and I. Which element has an ionisation enthalphy of 869 kJ mol-1 and 1142 kJmol-1 respectively?

• 5)

Explain why chlorine can be converted into chloride ion more easily as compared to fluoride ion from fluorine.

#### 11th Standard CBSE Chemistry Unit 2 Structure of Atom Book Back Questions - by Ashutosh Saran - Gurgaon - View & Read

• 1)

What is the experimental evidence in support of the idea that electronic energies in an atom are quantised?

• 2)

Which two discoveries put strong challenge to the Bohr model?

• 3)

The magnitude of charge on the electron is $4.8\times { 10 }^{ -10 }$ esu. What is the charge on the nucleus of a helium atom?

• 4)

What physical meaning is attributed to the square of the absolute value of wave function $|\psi |^{ 2 }$?

• 5)

An electron is in one of the 3d-orbitals .give the possible values of n, l, and m for this electron.

#### 11th Standard CBSE Chemistry Unit 1 Some Basic Concept of Chemistry Book Back Questions - by Ashutosh Saran - Gurgaon - View & Read

• 1)

The empirical formula of sucrose is

• 2)

The number of significant figures in 0.0101 is

• 3)

The number of grams of oxygen in 0.10 mol of Na2CO3· 10H2O is

• 4)

The mass of an atom of nitrogen is

• 5)

Using the unit conversion factor, express 1.54mm s-1 into pm $\mu$s-1.

#### 11th Standard CBSE Chemistry Unit 9 Hydrogen One Mark Question and Answer - by Ashutosh Saran - Gurgaon - View & Read

• 1)

Hydrogen gas is generally prepared by the

• 2)

Hydrogen peroxide is used as

• 3)

Water may be softened using

• 4)

On treatment of hard water with zeolite, sodium ions get exchanged with

• 5)

Calgon, which is used as a water softener, has the formula

#### 11th Standard CBSE Chemistry Unit 8 Redox Reactions One Mark Question and Answer - by Ashutosh Saran - Gurgaon - View & Read

• 1)

Among the following molecules, in which does bromine show the maximum oxidation number?

• 2)

Which of the following halogens do not exhibit a positive oxidation number in their compounds?

• 3)

Which of the following is most powerful oxidizing agent in the following

• 4)

On the reaction 2Ag + 2H2SO4 $\rightarrow$ Ag2So4 + 2H2O+SO2  sulphuric acid acts as

• 5)

The oxidation number of the carboxylic carbon atom in CHCOOH is

#### 11th Standard CBSE Chemistry Unit 7 Equilibrium One Mark Question and Answer - by Ashutosh Saran - Gurgaon - View & Read

• 1)

The equilibrium expression, Kc= [CO2] represents the reaction.

• 2)

Hydrogen molecule (H2) can be dissociated into hydrogen atoms (H). Which one of the following changes will not increase the number of atoms present at equilibrium?

• 3)

A catalyst will increase the rate of a chemical reaction by

• 4)

What is the correct expression for the representation of the solubility product constant
of Ag2 CrO4 ?

#### 11th Standard CBSE Chemistry Unit 6 Thermodynamics One Mark Question with Answer - by Ashutosh Saran - Gurgaon - View & Read

• 1)

A thermodynamic state function is a quantity

• 2)

For the process to occur under adiabatic conditions, the correct condition is:

• 3)

As per the available data:

• 4)

Thermodynamics is applicable to

• 5)

An isochoric process takes place at constant

### CBSE Education Study Materials

#### 11th CBSE Chemistry 2019 - 2020 Academic Syllabus - by Ashutosh Saran - Gurgaon Aug 21, 2019 Aug 21, 2019

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#### CBSEStudy Material - Sample Question Papers with Solutions for Class 11 Session 2020 - 2021

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