(iii) Manganese exhibits all the oxidation states from + 2 to + 7. It shows largest number of oxidation states as it has the maximum number of unpaired electrons.

(ii)Role of NaCN in the extraction of gold In this process, leaching of gold ore occurs in the presence of air from which the gold is obtained later by displacement method.
4Au(s) + 8CN^-(aq) + 2H₂O(aq) + O₂(9) ⟶ 4[Au(CN)₂]^- + 4OH^-(aq)
2[Au(CN)₂](aq) + Zn(s) ⟶ [Zn(CN)₄]^2-(aq) + 2Au(s)
(iii) Copper matte (containing Cu₂S and FeS ) is obtained by the fusion of roasted copper sulphide concentrated ores. It is done to separate the copper sulphide from the gangue and other metals that floats on the surface of the melt

(i) \({ CH }_{ 3 }{ CH }_{ 2 }OH\overset { { PCl }_{ 5 } }{ \longrightarrow } { CH }_{ 3 }{ CH }_{ 2 }Cl\)
(ii) \({ CH }_{ 3 }-C1+{ CH }_{ 3 }{ CH }_{ 2 }-ONa\longrightarrow { CH }_{ 3 }{ CH }_{ 2 }-O-{ CH }_{ 3 }\)

(i) Vitamin A 
(ii) Uracil 
(iii) It suggests that six carbon atoms are in straight chain/CHO-(CHOH)₄-CH₂OH 

(i) It is an antacid and helps in removing acidity of stomach.
(ii) As the water contain Ca²⁺ ions, therefore it is hard water. Hence synthetic detergents are preferred over the soaps for cleaning the clothes because calcium salts of detergents are soluble in water while calcium salts of soap are insoluble. As a result, lot of soap is wasted.
(iii) 0.2% solution of phenol is used as an antiseptic where as 1% solution of phenol acts as a disinfectant.

2\(\times\)10¹³sec.

\({ { \wedge } }^{ o }\)= 359.9 S cm², \(\alpha\) = 0.278

Those polymers in unsaturated monomers combine together without loss of any molecule are called addition polymers.

There are two types of addition polymers:
(i) Homopolymers: when addition polymerisation of single monomeric species take places, the polymer formed are called homopolymers, e.g. polythene is homopolymer.
(ii) Copolymers: The polymer made by addition polymerisation from two different monomers are called copolymers, .g. Buna-S is copolymer of 1,3-butadiene and styrene.

(i) Since size of S is more than that of 0, the distance between central atom and hydrogen atoms is more in \({ H }_{ 2 }S\)  than in \({ H }_{ 2 }O\). Therefore, bond dissociation enthalpy of \({ H }_{ 2 }S\) is less and bond cleavage is more easy than in \({ H }_{ 2 }O\) . Therefore, \({ H }_{ 2 }S\)  is more acidic than \({ H }_{ 2 }O\).
(ii) In the resonance structures of \({ NO }_{ 2 }^{ - }\), two bonds are sharing a double bond, while in \({ NO }_{ 3 }^{ - }\), three bonds4 are sharing a double bond.
As a result, the bond in \({ NO }_{ 2 }^{ - }\)will be shorter than in \({ NO }_{ 3 }^{ - }\) and therefore, N-O bond length in \({ NO }_{ 2 }^{ - }\)  is shorter than N-O in \({ NO }_{ 3 }^{ - }\).
(iii)The larger tendency of oxygen to stabilise the higher oxidation state is because of the tendency of oxygen to form multiple bonds with metal.

If a is the edge length of fcc unit cell, then
face diagonal = 4r
\(4r=\sqrt { 2 } a\)
\( r=\frac { \sqrt { 2 } }{ 4 } a\)
\(=\frac { \sqrt { 2 } \times 400pm }{ 4 } \)
\(=1.414\times 100=141.4pm\) 
​

(i) Micelles: Soaps and detergents consist of lyophilic and lyophobic parts which associate together to form micelles.
(ii) Peptization: The conversion of precipitate into colloidal solution in presence of peptizing agent is called peptization. The peptizing agent is generally an electrolyte. In this process, a dispersion medium (liquid) breaks up the precipitate into the colloidal state. Lyophilic sols are prepared by bringing into contact or warming the substance with a dispersion medium, e.g. gelatin, gum arabic, starch and soaps are easily peptized by water. Cellulose nitrate is peptized by organic solvents, such as ethyl alcohol. The product obtained is commercially known as collodion.
(iii) Desorption: The process of removing an adsorbed substance from a surface on which it is adsorbed is called desorption. Silica gel removes water, animal charcoal removes color from the surface of organic compounds.

(a) The alkyl group in cyclohexanol is more compact than the alkyl group in Hexanol-1. The -OH group of cyclohexanol is more exposed and is more available for Hydrogen bonding with water. Hence, Cyclohexanol is more soluble in water than hexanol-1.
(b) In Propane1, 3-diol, there are two - OH groups present which increase the no. of H bonds between water and the diol. Hence Propane 1, 3-diol is more soluble in water than propan-1-ol. .

(i) Because + 5 oxidation state is more covalent than +3/ high charge to size ratio/high polarizing power.
(ii) Because HC1 is a mild oxidising agent and formation of hydrogen gas prevents the formation of FeC1₃.
(iii) Because of resonance in O₃ molecule.

Europium (II) has electronic configuration [Xe] 4f 5do while cerium (II) has electronic configuration [Xe] 4f 5d1. In Eu²⁺, 4f - subshell is half filled and 5d-subshell is empty. Since half filled and completely filled electronic configurations are more stable, the Eu²⁺ ion is more stable than Ce²⁺in which neither 4f subshell nor 5d-subshell is half filled or completely filled.

Reactions taking place in nickel cadmium battery. This is also a rechargeable cell. The main electrode reactions are:
At anode
\(Cd(s)+2{ OH }^{ - }(aq)\longrightarrow Cd{ \left( OH \right) }_{ 2 }(s)+{ 2e }^{ - }\)
At cathode
\( { NiO }_{ 2 }(s)+2{ H }_{ 2 }O+{ 2e }^{ - }\longrightarrow Ni{ \left( OH \right) }_{ 2 }+2{ OH }^{ - }(aq)\)
In these reactions, there is no formation of gaseous products. The reaction products generally remain sticking to the electrodes and can be reconverted by charging the cell. The charging process is similar to lead storage battery.

An ideal solution may be defined as the solution which obeys Raoult's law exactly over the entire range of temperature and pressure. For ideal solution
(i) Heat of mixing zero
(ii) Volume change of mixing is zero.

When benzylamine is treated  with HNO₂, benzyldiazonium chloride is first formed whivh being unstable decomposes to form benzyl alcohol.

OH^- being a strong base is a bad leaving group. When H₂SO₄ is added, protonation of alcohol occurs i.e -OH is converted into \(-\stackrel{+}{\mathrm{O}} \mathrm{H}_{2}\)

Molarity of solution = \(\frac { 0.025\ mole }{ 0.200\ L } =0.125\ M\)

The various quantities known to us are as follows:
\(p_{1}^{0}=0.850 \text { bar; } p=0.845 \text { bar; } M_{1}=78 \mathrm{~g} \mathrm{~mol}^{-1} ; w_{2}=0.5 \mathrm{~g} ; w_{1}=39 \mathrm{~g}\)
\(\frac{0.850 \mathrm{\ bar}-0.845 \mathrm{\ bar}}{0.850 \mathrm{ \ bar}}=\frac{0.5 \mathrm{~g} \times 78 \mathrm{~g} \mathrm{~mol}^{-1}}{M_{2} \times 39 \mathrm{~g}}\)
Therefore, M₂ = 170 g mol^–1

The process of forming polymers from two or more different monomeric units is called copolymerization. Multiple units of each monomer are present in a copolymer. The process of forming polymer Buna-S from 1, 3-butadiene and styrene is an example of copolymerization.

(i)The chemical formula of the compound is shown. Its name is cis-diammine dichlorido platinum (II).
(ii) It behaves as an anti cancer agent by taking part in the chelate formation or chelation.
(iii) In the trans isomer the similar groups are on opposite sides and chelate formation does not take place.
(iv) Cis-platin saves many valueable lives by forming co-ordinate complex. So it is life saving.

(i) It is Deoxyribo Nucleic acid.
(ii) Base thymine is present in DNA and not in RNA.
(iii) Base uracil is present in RNA and not in DNA.
(iv) Allee was having scientific attitude.

(i) Dust and smoke coming out of chimney can be controlled by installing cottrell smoke precipitator. 
(ii) Cottrell precipitator consists of two metal discs charged to a high electrical potential. The charge on colloidal dust and carbon particles of smoke is neutralised and they get precipitated while free gases escape out of chimney. 
(iii) The knowledge of cottrell precipitator and management of dust and carbon particles of smoke can help us to clean our environment and make it healthier. Eco-friendliness and self-awareness are values associated with it.

Aluminium vessels are not affected either by acids or alkalies or by other chemicals, but copper and bronze vessels react with these forming poisonous chemical compounds.That's why, vessels are made up of aluminium are preferred.

SBR (styrene-butadiene rubber) is an addition copolymer.

SiO₂ used as an acidic flux

An emulsion can be broken by heating or cooling, i.e., (a) and (b) and not by (b) and (d).