(a) Give reasons for the following:
(i) Sulphur in vapour state shows paramagnetic behaviour:
(ii) N-N bond is weaker than P-P bond:
(iii) Ozone is thermodynamically less stable then oxygen.
(b) Write the name of the gas released when $\mathrm{Cu}$ is added to
(i) Dilute ${\mathrm{HNO}}_3$
(ii) Conc. ${\mathrm{HNO}}_3$
OR
(a) (i) Write the disproportionation reaction of ${\mathrm{H}}_3{\mathrm{PO}}_3$
(ii) Draw the structure of ${\mathrm{XeF}}_4$.
(b) Account for the following:
(i) Although fluorine has less negative electron gain enthalpy yet ${\mathit{F}}_2$ is a strong oxidizing agent.
(ii) Acidic character decreases from ${\mathrm{N}}_2{\mathrm{O}}_3$ to ${\mathrm{Bi}}_2{\mathrm{O}}_3$ in group 15.
(c) Write a chemical reaction to test sulphur dioxide gas. Write the chemical equation involved..