(i) (A) is more stable than (B).
(ii) Carbocation (A) is more planar and is stabilised by resonance.
(iii) Carbocation (B) is non-planar and does not undergo resonance.
(iv) Double bond inside the ring is more stable than outside the ring.

If the water is not the solvent, the solution is non- aqueous solution. (Benzene, CCI₄, ether etc., act as solvent in these solutions).

(i) Green chemistry is a chemical philosophy encouraging the design of products and Processes that reduce or eliminate the use and generation of hazardous substances.
(ii) For this, scientist are trying to develop methods to produce eco-friendly compounds. This can be best understood by considering the following example in which styrene is produced both by traditional and greener routes. To avoid carcinogenic benzene, greener route is to start with cheaper and environmentally safer xylenes.
(iii) Green chemistry means science of environmentally favourable chemical synthesis.

This is one method to purify and separate liquids present in the mixture having their boiling point close to each other. In the fractional distillation, a fractionating column is fitted with distillation ask and a condenser. A thermometer is fitted in the fractionating column near the mouth of the condenser. This will enable to record the temperature of vapour passing over the condenser. The process of separation of the components in a liquid mixture I at their respective boiling points in the form of vapours and the subsequent condensation of those vapours is called fractional distillation. The process of fractional distillation is repeated. This method finds remarkable application in distillation of petroleum, coal-tar and crude oil.

\(K_{eq}={[Fe(SCN)]^{2+}\over [Fe^{3+}][SCN^-]}\)
\(={2\times 10^{-4}M\over 8\times 10^{-4}M\times 6\times 10^{-4}M}\)
= 0.0416 x 10⁴
K_eq = 41.6 x 10² M^-1

Molar mass of oxalic acid (H₂C₂O₄) = 2 x 1 + 2 x 12 + 4 x 16 = 90
Basicity of oxalic acid = 2
Equivalent Mass = \(\frac { 90 }{ 2 } =45g\) eq^-1

Lithium iodide shows covalent character, as Li⁺ ion, being smaller exerts high polarising power on the iodide anion. Alternatively, the iodide ion being the largest can be polarised to a greater extent by Li⁺ ion. Hence, lithium iodide is covalent.

Heavy water is toxic when taken in large quantities. Heavy water is not radioactive. The deuterium in it is stable; it does not decay. Nobody will be in danger at all from radiation. It is heavier than plain water. D₂O performs little different from H₂O in chemical reactions. One has to drink a lot of D₂O to kill him.

The calorific value is defined as "The amount of heat produced in calories (or joules) when one gram of the substance is completely burnt." The SI unit of calorific value is J kg^-1. It is usually expressed in cal g ^-1.

Mg (OH)₂ ; Magnesium hydroxide.

Mg + I.E₁ ⟶ Mg⁺ +1e^-     .....(i)
Mg⁺ + I.E₂ ⟶ Mg²⁺ + 1e^-  ....(ii)
Mg²⁺ + I.E₃ ⟶ Mg³⁺ + 1e^-  ....(iii)
(i) The step (iii) which involves the formation of Mg³⁺ requires higher ionisation energy.
(ii) Mg²⁺ consist of 10 electrons (2, 8) attaining the stable noble gas configuration of argon (Z = 10).
(iii) Since the valence orbital is completely filled, more energy will be required to remove electrons.

According to Le Chatelier's principle, the effect of increase in concentration of a substance is to shift the equilibrium in a direction that consumes the added substance.
Let us consider the reaction
\({ H }_{ 2 }\left( g \right) +{ I }_{ 2 }\left( g \right) \rightleftharpoons 2HI\left( g \right) \)
The addition of H₂ or I₂to the equilibrium mixture, disturbs the equilibrium. In order to minimize the stress, the system shifts the reaction in a direction where H₂ and I₂ are consumed i.e., the formation of additional HI would balance the effect of added reactant. Hence, the equilibrium this to the right (forward direction) i.e. the forward reaction takes place until the equilibrium is re established. Similarly, removal of HI (product) also favours the forward reaction.

(i) Brominatin of alkene to give bromo alkane.

(iii) In this reaction, benzoyl peroxide acts as a radical initiator. The mechanism involves free radicals.
\({ H }_{ 2 }C=CH+H-Br\overset { \overset { Benzoyl }{ Peroxide } }{ \longrightarrow } C{ H }_{ 3 }-C{ H }_{ 2 }-Br\)

(w) = 0.33 g
(c) = 0.397 g
\(\% I=\frac{127}{235} \times \frac{c}{w} \times 100=\frac{127}{235} \times \frac{0.235}{0.40} \times 100=31.75 \%\)

for the reaction,
SrCO₃ (S) ⇌ SrO(S) + CO₂(S)
Δn_g = 1 – 0 = 1
\(\therefore\) K_P = K_C (RT)
2.2 x 10^–24 = K_C (0.0821) (1002)
\(K_c={2.2\times 10^{-4}\over 0.0821\times 1002}\)
KC = 2.674 x 10^-6

(a) D₂O retards the growth of living organisms like plants and animals.
(b) Pure heavy water kills small fishes, tadpoles and mice when fed upon it.

\({ r_{n} }=\frac{(0.529)n^2}{z}\mathring{A}\ \ { E_{n} }=\frac{-13.6(z)^2}{(n)^2}ev atom^{-1}\)
for Li²⁺ z = 3
Bohr radius for the third orbit (r₃)
= \(\frac { (0.529){ (3) }^{ 2 } }{ 3 } \)
= 0.529\(\times\)3
=1.587 \(\mathring{A}\)
Energy of an electron in the fourth orbit
\(({E}_{6})=\frac { -13.6{ (3) }^{ 2 } }{ { (4) }^{ 2 } } \)
=-7.65eV atom^-1

\(\triangle x.\triangle p\ge \frac { h }{ 4\pi } \)
\(\triangle x.\triangle p\ge 5.28 \times{ 10 }^{ -35 }Kg{ m }^{ 2 }{ s }^{ -1 }\)
\(\triangle x.(m\triangle v)\ge 5.28 \times{ 10 }^{ -35 }Kg{ m }^{ 2 }{ s }^{ -1 }\)
Given \(\triangle\)v = 0.1%
v = 2.2 x 106 ms^-1
m = 9.1 x 10^-31Kg
\(\triangle\)v = \(\frac{0.1}{100}\times2.2\times{10}^{6}ms^{-1}\)
= \(2.2\times{10}^{6}ms^{-1}\)
\(\therefore \triangle x\ge \frac { { 5.28\times 10 }^{ -35 }{ Kgm }^{ 2 }{ s }^{ -1 } }{ 9.1\times { 10 }^{ -31 }Kg\times 2.2\times { 10 }^{ 3 }m{ s }^{ -1 } } \)
\(\\ \triangle x\ge 2.64\times { 10 }^{ -8 }m\)

The larger the size of the molecule, the greater will be Van der Waals' attraction. Therefore greater the deviation from ideal behaviour. So bromine will deviate more from ideal behaviour because it has bigger atoms.

(a) Given V₁ = 25 ml V₂ = 40 ml
M₁ = 0.312m M₂ = ?
V₁M₁ = V₂M₂
250 x 0.312 = 40 x M2
M₂ = \(\frac { 25\times 0.312 }{ 40 } \)
M₂ = 0.195M
(b) Given V₁ = 25 ml V₂ = 100 ml
M₁ = 0.312m M₂ = ?
V₁M₁ = V₂M₂
250 x 0.312  = 100 x M₂
M₂ = \(\frac { 25\times 0.312 }{ 40 } \)
M₂ = 0.078M
Given V₁ = 25 ml V₂ = 100 ml
M₁ = 0.312m M₂ = ?
V₁M₁ = V₂M₂
M2 = \(\frac { 25\times 0.321 }{ 350 } \)
= 0.022M

This method is based upon the fact that nitrogenous compound when heated with cupric oxide in an atmosphere of CO₂ yields free nitrogen. Thus
\({ C }_{ x }{ H }_{ y }{ N }_{ z }+\left( 2x+\frac { y }{ 2 } \right) CuO\longrightarrow xCO_{ 2 }+\frac { y }{ 2 } H_{ 2 }O+\frac { Z }{ 2 } { N }_{ 2 }+\left( 2x+\frac { y }{ 2 } \right) Cu\)
Traces of oxide of nitrogen, which may be formed in some cases, are reduced to elemental nitrogen by passing over heated copper spiral. The apparatus used in Dumas method consists of CO₂ generator, combustion tube, Schiffs nitrometer.
CO₂ generator:
CO₂ needed in this process is prepared by heating magnetite or sodium bicarbonate contained in a hard glass tube or by the action of dil. HCI on marble in a Kipps apparatus. The gas is passed through the combustion tube after being dried-by bubbling through cone. H₂SO₄,
Combustion Tube:
The combustion tube is heated in a furnace is charged with a) a roll of oxidized copper gauze to prevent the back diffusion of the products of combustion and to heat the organic substance mixed with CuO by radiation b) a weighed amount of the organic substance mixed with excess of CuO, c) a layer of course CuO packed in about 2/3 of the entire length of the tube and kept in position by loose asbestos plug on either side; this oxidizes the organic vapors passing through it, and d) a reduced copper spiral which reduces any oxides of nitrogen formed during combustion to nitrogen.
Schiff's nitro meter: 
The nitrogen gas obtained by the decomposition of the substance in the combustion tube is mixed with considerable excess of CO₂ It is estimated by passing nitrometer when CO₂ is absorbed by KOH and the nitrogen gets collected in the upper part of graduated tube.
Procedure:
To start with the tap of nitrometer is left open CO₂ is passed through the combustion tube to expel the air in it. When the gas bubbles risin through, the potash solution fails to reach the top of it and is completely absorbed it shows that only CO₂ is coming and that all air has been expelled from the combustion tube. The nitrometer is then and the tap is closed. The combustion tube is now heated in the furnace and the temperature rises gradually. The nitrogen set free from the compound collects in the nitrometer. When the combustion is complete a strong current of CO₂ is sent through, the apparatus in order to sweep the last trace of nitrogen from it. The volume of the gas gets collected is noted after adjusting the reservoir so that the solution in it and the graduated tube is the same. The atmospheric pressure and the temperature are also recorded.

Calulations: 
Weight of the substance taken = wg
Volume of nitrogen = V₁L
Room temperature =T₁K
Atmospheric pressure = P mm of Hg 
Agueen tension at
room temperature = p¹ mm ofHg
Pressure of dry nitrogen = (P - p¹) = PI mm of Hg.
Let P_o V_o and T_o be the pressure, Volume and temperature respectively of dry nitrogen at STP,
Then, \(\frac { { P }_{ 0 }{ V }_{ 0 } }{ { T }_{ 0 } } =\frac { { P }_{ 1 }{ V }_{ 1 } }{ { T }_{ 1 } } \)
\(\therefore { V }_{ 0 }=\frac { { P }_{ 1 }{ V }_{ 1 } }{ { T }_{ 1 } } \times \frac { { T }_{ 0 } }{ { P }_{ 0 } } \)
\({ V }_{ 0 }=\left( \frac { { P }_{ 1 }{ V }_{ 1 } }{ { T }_{ 1 } } \times \frac { 273K }{ 760 } \right) \)
Calculation of percentage of nitrogen. 22.4 L of N₂ at STP weigh 28g of N₂
\(\therefore \) V0 L of N2 at S.T.P weigh \(\frac { 28 }{ 22.4 } \times { V }_{ 0 }\)
wg of organic compound contain \(\left( \frac { 28 }{ 22.4 } \times \frac { { V }_{ 0 } }{ W } \right) \)
\(\therefore \) Percentage of nitrogen= \(\left( \frac { 28 }{ 22.4 } \times \frac { { V }_{ 0 } }{ W } \right) \times 100\)

(i) \(\underset { chloroform }{ CH{ Cl }_{ 3 } } +\frac { 1 }{ 2 } { O }_{ 2 }\overset { Air }{ \underset { Light }{ \longrightarrow } } \underset { Phosgene }{ CO{ Cl }_{ 2 }+HCl } \)
(ii) \(\underset { carbonTetraChloride }{ C{ Cl }_{ 4 } } +{ H }_{ 2 }O\overset { \triangle }{ \underset { Light }{ \longrightarrow } } \underset { Phosgene }{ CO{ Cl }_{ 2 } } +2{ H }_{ 2 }O\)
(iii) 

(iv)\(H-\overset { \underset { | }{ H } }{ \underset { \overset { | }{ H } }{ C } } -\overset { \underset { | }{ H } }{ \underset { \overset { | }{ H } }{ C } } -H+2KOH\overset { { C }_{ 2 }{ H }_{ 5 }OH }{ \underset { \triangle }{ \longrightarrow } } HC\equiv \underset { Acetylene }{ CH } +2KCl+{ H }_{ 2 }O\)
Ethylidene dichloride
(v) \(\underset { \overset { | }{ OH } }{ { CH }_{ 2 } } -\underset { \overset { | }{ OH } }{ { CH }_{ 2 } } +2PC{ l }_{ 5 }\longrightarrow \underset { \overset { | }{ Cl } }{ { CH }_{ 2 } } -\underset { \overset { | }{ Cl } }{ { CH }_{ 2 } } +2POC{ l }_{ 3 }+2HCl\)
Ethylene Glycol                                   Ethylene dichloride

Rain water normally has a pH of 5.6 due to dissolution of atmospheric CO₂ into it. Oxides of sulphur and nitrogen in the atmosphere may be absorbed by droplets of frater that make up clouds and get chemically converted into sulphuric acid and nitric acid respectively as a results of pH of rain water drops below the level 5.6, hence it is called acid rain. Acid rain is a by-product of a variety of sulphur and nitrogen oxides in the atmosphere. Burning of fossil fuels (coal and oil) in power stations, furnaces and petrol, diesel in motor engines produce sulphur dioxide and nitrogen oxides The main contributors of acid rain are SO₂ and NO₂.They are converted into sulphuric acid and nitric acid respectively by the reaction with oxygen and water.
2SO₂ + O₂ + 2H₂O ⟶ 2H₂SO₄
4NO₂ + O₂ + 2H₂O ⟶ 4HNO₃
Harmful effects of acid rain
Some harmful effects are discussed below :
(i) Acid rain causes extensive damage to buildings and structural materials of marbles. This attack on marble is termed as Stone leprosy.
CaCO₃ + H₂SO₄ ⟶ CaSO₄ + H₂O +CO₂ ↑
(ii) Acid rain affects plants and animal life in aquatic ecosystem.
(iii) It is harmful for agriculture, trees and plants as it dissolves and removes the nutrients needed for their growth.
(iv) It corrodes water pipes resulting in the leaching of heavy metals such as iron, lead and copper into the drinking water which have toxic effects.
(v) It causes respiratory ailment in humans and animals.

(i) Hydrogen bond :
When a hydrogen atom (H) is covalently bonded to a highly electronegative atom (F or °or N), the bond is polarized in such a way that the hydrogen atom is able to form a weak bond (electrostatic attraction) between the hydrogen atom of a molecule and the electronegative atom of a second molecule. The bond thus formed is called a hydrogen bond.
(ii) Intermolecular Hydrogen:
Intermolecular hydrogen bonds occur between two separate molecules.
They can occur between any numbers of like or unlike molecules as long as hydrogen donors and acceptors are present and in positions in which they can interact. Eg: Water, HF, etc, 
(iii) Intramolecular Hydrogen: 
This type of bond is formed between hydrogen atom and N, O or F atom of the same molecule.
This type of hydrogen bonding is commonly called chelation and is more frequently found in organic compounds. Eg: o-nitro phenol, salicylic acid, etc.

Empirical formula = Na₂ SH₂₀ O₁₄ 
\(\left[ \begin{matrix} { Na }_{ 2 }{ SH }_{ 20 }{ O }_{ 14 } \\ =(2\times 23)+(1\times 32)+(20\times 1)+14(16) \\ =46+32+20+234 \\ =322 \end{matrix} \right] \)
n = \(\frac { molar\quad mass }{ caluclated\quad empirical\quad formula\quad mass } =\frac { 322 }{ 322 } =1\)
Molecular formula = Na₂ SH₂₀O₁₄
Since all the hydrogen in the compound are present as water
\(\therefore \) The molecular formula is Na₂ SO₄ 10H₂O.

(i) Alkaline earth metal (A) belonging to 3rd period is magnesium.
(ii) So A is Magnesium. Magnesium reacts with oxygen and nitrogen as follows.
\(2Mg+O_2⟶\underset{(B)}{2MgO}\)
\(3Mg+N_2⟶\underset{(C)}{Mg_3N_2}\)
So B is Magnesium oxide and C is magnesium nitride.
(iii) Magnesium undergoes metal displacement reaction with AgNO₃ as follow to give D as follows :
\(Mg+2AgNO_3⟶\underset{D}{Mg(NO_3)_2}+2Ag\)
So D is Magnesium nitrate.
Result  :