Question

Among the following the correct statement is :

• A. between $N{H}_3$ and $P{H}_3,N{H}_3$ is a better electron donor because the lone pair of electrons occupies spherical ${}^{\prime }{s}^{\prime }$ orbital and is less directional
• B. between $N{H}_3$ and $P{H}_3,N{H}_3$ is a better electron donor because the lone pair of electrons occupies $s{p}^2$ orbital and is more directional
• C. between $N{H}_3$ and $P{H}_3,N{H}_3$ is a better electron donor because the lone pair of electrons occupies $s{p}^3$ orbital and is more directional
• D. between $N{H}_3$ and $P{H}_3,P{H}_3$ is a better electron donor because the lone pair of electrons occupies spherical ${}^{\prime }{s}^{\prime }$ orbital and is less directional

Answer 1

The correct option is C between $N{H}_3$ and $P{H}_3,N{H}_3$ is a better electron donor because the lone pair of electrons occupies $s{p}^3$ orbital and is more directional

$N{H}_3$ is a better electron donor than $P{H}_3$ because the lone pair of the electrons on the nitrogen atom occupies a $s{p}^3$ hybridized orbital and is more directional due to a smaller size of $N-atom$ when compared to $P.$

Also, on moving down a group, the bond angle decreases due to more $P$ character in the bond pair and simultaneously more $S$ character in lone pair orbital.

Answer is option $C.$