Explain the following facts giving appropriate reasons in each case :
(i) is an exothermic compound whereas is not.
(ii) All the bonds in are not equivalent.
(i) The bond energy of F-F bond is lower than that of N-F bond so is an exothermic compound. On the other hand bond energy of Cl-Cl bond is higher than that of N-Cl bond so is an endothermic as well as unstable compound.
(ii) has trigonal bipyramidal structure in which one position of equitorial is occupied by a lone pair of electrons. Sulphur undergoes hybridisation and has sea-saw geometry.