Question

Structure of ammonia is :

• A. square planar
• B. tetrahedral
• C. trigonal
• D. trigonal pyramidal

Answer 1

The correct option is D trigonal pyramidal

The hybridization of ammonia, $N{H}_3$ is $s{p}^3$ with $3$ sigma bond pairs and $1$ lone pair of electrons on the central nitrogen atom.

From the hybridization, the molecule is expected to have a tetrahedral shape, but according to the VSEPR theory, there is a repulsion between the lone pair and the adjacent bond pairs.

Hence, its shape is distorted from tetrahedral $\left({109.5}^{\circ }bondangle\right)$ to 'trigonal pyramidal' $\left({107}^{\circ }bondangle\right)$ as shown in the figure.

Therefore, option (D) is the correct answer.