(i) Since, the byproduct of roasting of sulphide ore is SO₂' It also turns lime water milky. Therefore, gas 'B ' must be SO_2.
(ii) As the gas B is obtained when amorphous solid 'A' burns in air therefore, amorphous solid 'A' must be sulphur, S₈
\(\begin{aligned} &\mathrm{S}_{8}+8 \mathrm{O}_{2} \stackrel{\Delta}{\longrightarrow} 8 \mathrm{SO}_{2}\\ &\text { (A) }\\ &2 \mathrm{ZnS}(s)+3 \mathrm{O}_{2}(g) \longrightarrow 2 \mathrm{ZnO}(s)+2 \mathrm{SO}_{2} \end{aligned}\)
(iii) Gas B reduces acidified aqueous KMnO₄ solution and reduces Fe³⁺ to Fe²⁺ salts as shown below:
\(2 \mathrm{MnO}_{4}^{-}+5 \mathrm{SO}_{2}+2 \mathrm{H}_{2} \mathrm{O} \longrightarrow 5 \mathrm{SO}_{4}^{2-}+4 \mathrm{H}^{+}+2 \mathrm{Mn}^{2+}\\ (Violet) (Colourless) \)
\(\\\underset{\text { (Yellow) }}{2 \mathrm{Fe}^{3+}}+\mathrm{SO}_{2}+2 \mathrm{H}_{2} \mathrm{O} \longrightarrow \underset{\text { (Green) }}{2 \mathrm{Fe}^{2+}}+\mathrm{SO}_{4}^{2-}+4 \mathrm{H}^{+}\)
Thus, solid A is S₈ and gas B is SO₂

The amide has the following resonating structures:
  
Due to the delocalisation of lone pair of electrons on N over C==O group, amino group acquires a positive charge which ma, es N-H bond weak. Moreover, the anion formed after removal of a proton is also stabilized by resonance as :
  
However, no such stabilization is possible in amines.

(i) tert-Butyl bromide being a 3° alkyl halide on treatment with a base (i.e. NH₃) prefers to undergo elimination rather than substitution. Therefore, the product is isobutylene rather than tert-butylamine.
 
1° amines containing tert-alkyl groups can be prepared by action of suitable Grignard reagents on O-methylhydroxylarnine. For example,

(i) (a) CuF2 (b) (i) Cr in crO²₄ - is in the highest oxidation state, i.e., +6 while Mn in MnO is in oxidation state +6 and its most stable oxidation state is +7
(ii) due to lanthanoid contraction
(iii) [Mn²⁺ has 3d 5 configuration]

CFC (chlorofluoro carbons) are responsible for the destruction of ozone layer and UV light can reach earth which may cause skin cancer and affect flora and fauna.
These compounds should be banned and their use should be made to minimum extent.

\({ \triangle }_{ t }=\left( \frac { 4 }{ 9 } \right) { \triangle }_{ 0 }\).  Thus,  \({ \triangle }_{ t }\) is smaller than \({ \triangle }_{ 0 }\).  Hence, less energy (higher wavelength) is absorbed by tetrahedral complexes than by octahedral complexes of the same metal and ligands.  Therefore, the observed colour are different.

When white light falls on the complex, some part of it is absorbed.  Greater the CFSE, greater is the energy absorbed or shorter is the wavelength absorbed \((E={hc\over\lambda })\).  The observed colour is the complementary colour of the colour absorbed.

(i) As isomer A reacts with AgNO₃ to give a white precipitate, CI must be present in the ionization sphere. As it does not react with BaCI₂, SO₄^2- must be present in coordination sphere.
Formula of A = [Co(NH₃)₅SO₄] CI (coordination no. of Co = 6) As reactions are reverse for isomer B, formula of B = [Co(NH₃)₅CI]S0₄
(ii) Ionization isomerism.
(iii) A = Pentaarnminesulphatocobalt (III) chloride ; B = Pentaamminechloridocobalt (ill) sulphate

\([Mn(CN)_6]^{3-}\)
d²sp³, (ii) inner orbital complex, (iii) paramagnetic, (iv) 2.87 B.M.
(i) d²sp³ (ii) Inner orbital complex, (iii) diamagnetic, (iv) \(\mu=0\)
(i) d²sp³, (ii) Inner orbital complex, (iii) paramagnetic, (iv) 3.87 B.M.
(i) sp³d², (ii) outer orbital complex (iii) paramagnetic (iv) 4.9 B.M.

(i) \([CoF_6]^{3-}\)
\( [Co(H_2O)_6]^{2+}\)
\([Co(CN)_6]^{3-}\)
(ii) \([FeF_6]^{3-}\)
\(\ [Fe(H_2O)_6]^{2+}\)
\([Fe(CN)_6]^{4-}\)
It is diamagnetic due to the absence of unpaired electrons.

(i) \({ NH }_{ 4 }{ NO }_{ 2 }(s)\underrightarrow { heat } { N }_{ 2 }+{ 2H }_{ 2 }O\) 
                'A'                 'B'
(ii) \({ N }_{ 2 }+{ 3H }_{ 2 }\longrightarrow 2{ NH }_{ 3 }(g)\) 
                              'C' basic
(iii) \({ 4NH }_{ 3 }+{ 5O }_{ 2 }\longrightarrow 4NO+{ 6H }_{ 2 }O\) 
\(\\ 2NO+{ O }_{ 2 }\longrightarrow { 2NO }_{ 2 }\) 
                  'D' (part of acid rain)
\({ 3NO }_{ 2 }+{ H }_{ 2 }O\longrightarrow 2{ HNO }_{ 3 }+NO\)

 \(2Pb{ { { { (NO }_{ 3 }) } } }_{ 2 }\xrightarrow { heat } 2PbO(s)+{ NO }_{ 2 }+{ O }_{ 2 }\)
                               Brown (A)
\({ 2NO }_{ 2 }(g)\overset { cooling }{ \rightleftharpoons } { N }_{ 2 }{ O }_{ 4 }(s)\)
                         (B) Colourless
\({ N }_{ 2 }{ O }_{ 4 }+2NO\overset { heat }{ \underset { 250k }{ \rightleftharpoons } } { 2N }_{ 2 }{ O }_{ 3 }(s)\)
                       (C) Blue solid

Resonating Structures of  \({ N }_{ 2 }{ O }_{ 4 }\)