The bond angle in $\mathrm{NF}_{3}\left(102.3^{\circ}\right)$ is smaller than $\mathrm{NH}_{3}\left(107.2^{\circ}\right) .$ This is because of

• A

  large size of F compared to H
• B

  large size of N compared to F
• Correct answer
  C

  opposite polarity of $\mathrm{N}$ in the two molecules
• D

  small size of $\mathrm{H}$ compared to $\mathrm{N}$

Solution

In $\mathrm{NF}_{3}$, $\mathrm{N}$ is less electronegative as compared to F but in $\mathrm{NH}_{3}$, it is more electronegative than $\mathrm{H}$. And in case of same central atom. as the electronegativity of other atoms increases, bond angle decreases, Thus, bond angle in $\mathrm{NF}_{3}$ is smaller than that in $\mathrm{NH}_{3}$ because of the difference in the polarity of $\mathrm{N}$ in these molecules.

Hence, the correct answer is option: 'C'.