Question

Which of the following molecule having least bond angle?

• A. $H_{2}Se$
• B. $H_{2}S$
• C. $N{F}_3$
• D. $P{F}_3$
• E. $P{H}_3$

Answer 1

Answer: (A)

$H_{2}Se$

All the compounds involve $s{p}^3$ hybridization. The bond angles for different compounds vary because of the presence of lone pairs. The bond angle in $N{F}_3$ is ${102}^o$. It has only one lone pair.

The bond angle in $P{F}_3$ is ${96}^o$. It has only one lone pair.
The bond angle in $P{H}_3$ is ${94}^o$. It has only one lone pair.
Boh $H_2$ and $H_{2}Se$ have two lone pairs. $Se$ is less electronegative than $S$. Hence, the electron pair will be less drawn towards $Se$ than $S$. In $S$, since, the electron pairs are more towards $S$, there will be more repulsion and hence greater bond angle than $Se$. The bond angle in $H_{2}Se$ is ${91}^o$. The bond angle in $H_{2}S$ is ${92.3}^o$C. $H_{2}Se$ has least bond angle.