By QB365 on 31 Dec, 2022
QB365 provides a detailed and simple solution for every Possible Questions in Class 11 Chemistry Subject - Important 3 Mark English Medium. It will help Students to get more practice questions, Students can Practice these question papers in addition to score best marks.
11th Standard
Chemistry
Answer All The Questions
Which contains the greatest number of moles of oxygen atoms
i) 1 mol of ethanol
ii) 1 mol of formic acid
iii) 1 mol of H2O
How fast must a 54g tennis ball travel in order to have a de Broglie wavelength that is equal to that of a photon of green light 5400\(\overset { 0 }{ A } \) ?
An ion with mass number 37 possesses unit negative charge. If the ion contains 11.1% more neutrons than electrons, Find the symbol of the ion.
Elements a, b, c and d have the following electronic configurations:
a: 1s2, 2s2, 2p6
b: 1s2, 2s2, 2p6, 3s2, 3p1
c: 1s2, 2s2, 2p6, 3s2, 3p6
d: 1s2, 2s2, 2p1
Which elements among these will belong to the same group of periodic table.
Write chemical equation for the following reactions.
i) reaction of hydrogen with tungsten (VI) oxide on heating.
(ii) hydrogen gas and chlorine gas.
Complete the following chemical reactions and classify them into
(a) hydrolysis (b) redox (c) hydration reactions.
(1) KMnO4 + H2O2 ➝
(2) CrCl3 + H2O ➝
(3) CaO + H2O ➝
Arrange NH3, H2O and HF in the order of increasing magnitude of hydrogen bonding and explain the basis for your arrangement.
Write balanced chemical equation for each of the following chemical reactions.
Rubidum with oxgen gas
A sample of gas has a volume of 8.5 dm3 at an unknown temperature. When the sample is submerged in ice water at 0 °C, its volume gets reduced to 6.37 dm3. What is its initial temperature ?
An unknown gas diffuses at a rate of 0.5 time that of nitrogen at the same temperature and pressure. Calculate the molar mass of the unknown gas.
The standard enthalpies of formation of SO2 and SO3 are -297 kJ mol-1 and -396 kJ mol-1 respectively. Calculate the standard enthalpy of reaction for the reaction: SO2 + \(\frac{1}{2}\)O2⟶SO3
For a chemical reaction the values of ΔH and ΔS at 300K are -10 KJ mole-1 and -20 J deg-1 mole-1 respectively. What is the value of ΔG of the reaction? Calculate the ΔG of a reaction at 600K assuming ΔH and ΔS values are constant. Predict the nature of the reaction.
Give the IUPAC names of the following compounds.
\({ CH }_{ 2 }-{ CH }_{ 2 }-\underset { \overset { | }{ OH } }{ CH } -CHO\)
Give the IUPAC names of the following compounds.
Give the IUPAC names of the following compounds.
Give the structure for the following compound.
1,3,5- Trimethyl cyclohex - 1 -ene
Give the structure for the following compound.
1, 3- Dimethylcyclohexane
What are electrophiles and nucleophiles ? Give suitable examples for each.
Give examples for the following types of organic reactions.
Electrophilic substitution.
Describe the mechanism of Nitration of benzene.
write all possible isomers for an aromatic benzenoid compound having the molecular formula C8H10
How will you prepare n propyl iodide from n-propyl bromide?
A hydrocarbon C3H6 (A) reacts with HBr to form compound (B). Compound (B) reacts with aqueous potassium hydroxide to give (C) of molecular formula C3H6O.what are (A) (B) and (C). Explain the reactions.
What would happen, if the greenhouse gases were totally missing in the earth’s atmosphere ?
How would you know whether a redox reaction is taking place in an acidic, alkaline or neutral medium?
How much volume of hydrogen is liberated when 0.12g of magnesium reacts with dilute hydrochloric acid ?
Write the name and deduce the atomic number of the following element
i. The second alkali metal
ii. The fourth noble gas
iii. The third halogen
iv. The first transition element
Define the following terms.
Define the Molar Heat of Sublimation
What is the nature of the reaction for the following?
(i) ΔG>0
(ii) ΔG<0
(iii) ΔG=0
Answers
Compound | Given No.of moles | No.of oxygen atoms |
---|---|---|
Ethanol - C2H5OH | 1 | 1\(\times\)6.022\(\times\)1023 |
Formic acid - HCOOH | 1 | 2\(\times\)6.022\(\times\)1023 |
Water - H2O | 1 | 1\(\times\)6.022\(\times\)1023 |
Formic acid |
De Broglie wavelength of the tennis ball equal to 5400 \(\overset { 0 }{ A } \).
m = 54 g
V = ?
\(\lambda=\frac{h}{mV}\)
\(V=\frac{h}{m\lambda}\)
\(\mathrm{v}=\frac{6.626 \times 10^{-34} \mathrm{JS}}{54 \times 10^{-3} \mathrm{~kg} \times 5400 \times 10^{-10} \mathrm{~m}}=2.27 \times 10^{-26} \mathrm{~ms}^{-1}\)
Atom | Uni- negative ion | |
number of electron | x-I | x |
number of protons | x-1 | x-1 |
number of neutrons | y | y |
Given that, y = x + 11.1% of x
\(=\left(x+\frac{11.1}{100} x\right)=x+0.111 x\)
Y = 1.111 x
mass number = 37
number of protons + number of neutrons = 37
(x -1) + 1.111x = 37
x+1.111x = 38
2.111x = 38
\(x=\frac{38}{2.11}\)
x = 18.009
x 18 (whole number)
ஃ Atomic number = x- 1 = 18 - 1 = 17
Mass number = 37
Symbol of the ion \({ _{ 17 }^{ 37 }{ Cl } }^{ - }\)
In the periodic table vertical columns are called groups.
Elements in the same vertical column posses similar number of electrons in the outer orbitals.
∴ Elements a and c belongs to group 18
Elements band d belongs to group 13
(i) WO3 + 3H2 ➝ W + 3H2O
(ii) H2 + Cl2 ➝ 2HCl.
(i) 2KMnO4 + 3H2O2 ➝ 2MnO2 + 2KOH + 2H2O + 3O2 (Redox reaction)
(ii) CrCl3 + 6H2O ➝ [Cr Cl2 (H2O)CI. 2H2O [Hydration reaction]
(iii) CaO + H2O ➝ Ca(OH)2 (Hydration reaction)
(i) The order : NH3 < H2O
(ii) Strength of H bond depends upon the atomic size and electronegativity of the other atom to which H atom is covalently bonded.
Since electronegativity of F > O > N, the strength of H-bond is in the order H-F......H > H - O......H > H-N......H.
H-bonds are much weaker than covalent bonds.
Rb + O2 ⟶ RbO2
V1 = 8.5 dm3 V2 = 6.37 dm3
T1 = ? T2 = 0o C = 273 K
\(\frac { { V }_{ 1 } }{ { T }_{ 1 } } =\frac { { V }_{ 2 } }{ { T }_{ 2 } } \)
\({ V }_{ 1 }\times \left( \frac { { T }_{ 2 } }{ { V }_{ 2 } } \right) ={ T }_{ 1 }\)
T1 = 364.28 K
\(\frac{rate_{unknown}}{rateN_2}=\sqrt{\frac{M_{N_2}}{M_{unknown}}}\)
\(0.5=\sqrt{\frac{28\ g\ mol^{-1}}{M_{unknown}}}\)
Squaring on both sides
\((0.5)^2=\frac{28gmol^{-1}}{M_{unknown}}\)
\(\Rightarrow M_{unknown}=\frac{28}{0.25}\) = 112 g mol-1
\(\Delta { H }_{ f }^{ 0 }\)(SO2) = - 297 kJ mol-1
\(\Delta { H }_{ f }^{ 0 }\)(SO3) = - 396 kJ mol-1
SO2 + \(\frac{1}{2}\)O2⟶SO3 \(\Delta { H }_{ r}^{ 0 }\)=?
\(\Delta { H }_{ r}^{ 0 }\)=\((\Delta { H }_{ f }^{ 0 })\)compound-Σ(ΔHf)elements
\(\Delta { H }_{ r}^{ 0 }\)=\(\Delta { H }_{ f }^{ 0 }\)(SO3)-(\(\Delta { H }_{ f }^{ 0 }\)(SO2) +\(\frac{1}{2}\)\((\Delta { H }_{ f }^{ 0 })\)(O2))
\(\Delta { H }_{ r}^{ 0 }\)=- 396 kJ mol-1 - (-297 kJ mol-1 + 0)
\(\Delta { H }_{ r}^{ 0 }\)=-396 kJ mol-1 + 297
\(\Delta { H }_{ r}^{ 0 }\)=-99 kJ mol-1
ΔH = -10 KJ mol-1 = - 10000 J mol-1
ΔS = -20 JK-1 mol-1
T = 300 K
ΔG = ?
ΔG = ΔH - TΔS
ΔG = -10 KJ mol-1 - 300 k x (-20 x 10-3 )kJ K-1 mol-1
ΔG = (-10 + 6) KJ mol-1
ΔG = -4 KJ mol-1
At 600 K
ΔG = -10 KJ mol-1 - 600 K x (-20 x 10-3) KJ K-1 mol-1
ΔG = (-10 + 12) KJ mol-1
ΔG = + 2 KJ mol-1
The value of ΔG is negative at 300K and the reaction is spontaneous, but at 600K the value ΔG becomes positive and the reaction is non spontaneous.
2 - hydroxybutanal
1 - bromobut - 2 - ene
2-ethoxypropane
a) Electrophiles:
Electrophiles are reagents that are attracted towards negative charge or electron rich center. They are either positively charged ions or electron deficient neutral molecules. All Lewis acids act as electrophiles.
Neutral molecules like SnCl4 can also act as an electrophile, as it has vacant d-orbitals which can accommodate the electrons from others.
Types | Examples | Electron deficiententity |
Neutral electrophiles | Carbon dioxide (CO2), dichlorocarbene (CCl2) |
C |
Aluminium chloride (AlCl3), boron trifluoride (BF3) and ferric chloride (FeCI3) | Metal (M) | |
Positively charged electrophiles | Carbocations(R+) | C+ |
Proton (H+) | H+ | |
Alkyl halides (RX) | X+ | |
Oxonium ion (H3O+) and nitrosonium ion (NO+) | O+ | |
Nitronium ion (+NO2) | N+ |
b) Nucleophiles:
Nucleophiles are reagents that has high affinity for electro positive centers. They possess an atom has an unshared pair of electrons, and hence it is in search for an electro positive centre where it can have an opportunity to share its elections to form a covalent bond, and gets stabilised.
They are usually negatively charged ions or electron rich neutral molecules (contains one or more lone pair of electrons). AII Lewis bases act as nucleophiles.
Types | Examples | Electron rich site |
Neutral molecules having unshared pair of electron | Ammonia (NH3) and amines (RNH2) | N: |
Water (H2O), alcohols(ROH) and ethers (R - O- R) |
:O: | |
Hydrogen sulphide (H2S) and thiols (RSH) |
:S: | |
Negatively, charged nucleophiles | Chlorides (Cl-), bromides (Br-) and iodides (I-) |
X- |
Hydroxide ( HO-), alkoxide (RO-) and Carboxlate ions (RCOO-) |
O- | |
Cyanide (CN-) | N- |
In this reaction an atom or a group of atoms attached to a carbon atom is replaced by a new atom or a group of atoms.
Here Y+ is an electrophile
Example : Nitration of Benzene
Benzene undergoes nitration reaction becasuse it is an elecron - rich system due to delocalised \(\pi\) electron. So it is easily attacked by electrophiles and gives substituted products.
Mechanism:
Step - I : Formafion of the electrophile:
Step - II : Formation of carbocation intermediate:
The electrophile attacks the aromatic ring to form a carbocation intermediate which is stabilised by resonance.
Step - III: Formation of nitro benzene:
The electrophile attacks the artomatic ring to fo
Without the heating caused by the greenhouse effect, earth's average surface temperature would be only about -18 oC (0 oF). Although the greenhouse effect is a naturally occurring phenomenon, it is intensified by the continuous emission of greenhouse gases into the atmosphere.
During the past 100 years, the amount of carbon dioxide in the atmosphere increased by roughly 30 percent and the amount of methane more than doubled.If these trends continue, the average global temperature will increase which can lead to melting of polar ice caps and flooding of low areas. This will increase incidence of infectious diseases like dengu., malaria, etc.
1. If H+ any acid appears on either side of the chemical equation, the reaction occurs in acidic solution.
2. If OH- or any base appears on either side of the chemical equation, the reaction occurs in basic solution.
3. If neither H+, OH- nor any acid or base is present in the chemical equation, the solution is neutral.
The balanced chemical equation for the reaction is
Mg + 2HCI \(\rightarrow\) MgCl2 + H2
Atomic mass of Mg = 24g mol-1
According to the equation,
1 mol of Mg (24 g) will liberate 1 mol of H2 = 22.4L at STP
24g of Mg = 22.4 L of H2 at STP
\(0.12g \ of \ Mg={22.4\over24}\times0.12g \ of H_2 \ at STP\)
= 0.112 L or
= 112 cm3 at STP
(i) Sodium (Z = 11)
(ii) krypton (Z = 36)
(iii) Bromine (Z = 35)
(iv) Scandium (Z = 21)
(i) System: A system is defined as any portion of matter (or universe) under thermodynamic.consideration, which is separated from the rest of the universe by real or imaginary boundaries.
(ii) Surroundings: Everything in the universe that is not the part of system and can interact with system is called as surroundings.
(iii) Boundary: Anything which separates the system from its surroundings is called boundary.
Molar Heat of Sublimation: Molar Heat of sublimation is defined as "The change in enthalpy when one mole of a solid is directly converted into the gaseous state at its sublimation temperature". For example, the heat of sublimation of iodine is represented as
I2(s)⟶I2(g) ΔHsub = + 62.42 KJ
(i) ΔG>0: The process is non-spontaneous and non-feasible.
(ii) ΔG<0: The process is spontaneous and feasible.
(iii) ΔG=0: The process is in equilibrium.