Question

Among the following statement which one is true?

• A. $N{H}_3$ is less soluble than $P{H}_3$ in water
• B. $N{H}_3$ is stronger base and stronger reducing agent than $P{H}_3$
• C. $N{H}_3$ has higher boiling point than $P{H}_3$ and has lower melting point than $P{H}_3$
• D. $P{H}_3$ is stronger reducing agent than $N{H}_3$ and it has lower critical temperature than $N{H}_3$

Answer 1

The correct option is D $P{H}_3$ is stronger reducing agent than $N{H}_3$ and it has lower critical temperature than $N{H}_3$

Due to larger atomic size of P the bond length of $P-H$ bond is larger and bond dissociation energy is smaller. Hence, $P{H}_3$ easily gets dissociated to give up $H_2$ gas. Therefore, $P{H}_3$ acts as stronger reducing agent than $N{H}_3$.
$N{H}_3$ is more soluble than $P{H}_3$ in water due to strong H bonding.