Question

Ammonia forms a large number of complexes with transition metal ions. Hybridisation easily explains the case of sigma donation capability of $N{H}_3$ and $P{H}_3$.
Choose the correct statement from the following:

• 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 's' 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 $s{p}^3$-orbital and is more directional.
• C. Electron density on N is higher than that on P and hence NH₃ acts as a better base than PH₃ .
• D. P-H bonds are more polar than N-H bonds.The smaller size of N makes NH₃ a good Lewis acid.

Answer 1

Answer: (B), (C)

The correct options are
B

Between $N{H}_3$ and $P{H}_3,N{H}_3$ is a better electron donor because the lone pair of electrons occupies $s{p}^3$-orbital and is more directional.

C

Electron density on N is higher than that on P and hence NH₃ acts as a better base than PH₃ .

$N{H}_3$ is stronger Lewis base than $P{H}_3$. Down the group, basic strength of hydrides decreases.