(a) Draw the structures of the following:

(i) ${H}_{2}{S}_{2}{O}_{8}$                                     (ii) $HCl{O}_{4}$

(b) How would you account for the following:

(i) $N{H}_{3}$ is a stronger base than $P{H}_{3}.$

(ii) Sulphur has a greater tendency for catenation than oxygen.

(iii) ${F}_{2}$ is a stronger oxidising agent than $C{l}_{2}.$