Question

The bond angle in $N{F}_3\left({102.3}^o\right)$ is smaller than $N{H}_3\left({107.2}^o\right)$. This is because of

• A. large size of $F$ compared to $H$
• B. large size of $N$ compared to $F$
• C. opposite polarity of $N$ in the two molecules
• D. small size of $H$ compared to $N$

Answer 1

The correct option is C opposite polarity of $N$ in the two molecules

In $N{F}_3$, $N$ is less electronegative as compared to $F$ but in $N{H}_3$, it is more electronegative than $H$. And in case of same central atom, as the electronegativity of other atoms increases, bond angle decreases. Thus, bond angle in $N{F}_3$ is smaller than that in $N{H}_3$ because of the difference in the polarity of $N$ in these molecules.