Question

Give reasons for the following:
(i) Oxygen is a gas but sulphur is a solid.
(ii) $O_3$ acts as a powerful oxidising agent.
(iii) $Bi{H}_3$ is the strongest reducing agent amongst all the hydrides of group $15$ elements.

Answer 1

i. In oxygen molecule intermolecular forces are weak van der Waal's forces which causes it to exist as gas while in sulphur strong $S=S$ is not formed so it exist in puckered structure and held together by covalent bond and exist as polymeric molecule.
ii. Ozone acts as a powerful oxidizing agent as it can produce nascent oxygen.
iii. On moving from top to bottom in hydrides of group $15$, bond length increases and the chances of hydrogen removal also increases so oxidation number also increases and $Bi{H}_3$ is the strongest reducing agent amongst all the hydrides of group $15$.