pBlock ElementsII 1 Question 72
67. The $\mathrm{H}-\mathrm{N}-\mathrm{H}$ bond angle in $\mathrm{NH}{3}$ is greater than the $\mathrm{H}-\mathrm{As}-\mathrm{H}$ bond angle in $\mathrm{AsH}{3}$.
(1984, 1M)
Show Answer
Solution:
- Both ’ $\mathrm{N}$ ’ and ‘As’ in corresponding hydrides are $s p^{3}$-hybridised. If central atoms are from same group, bond angle decreases from top to bottom if all other things are similar. Hence, $\mathrm{H}-\mathrm{N}-\mathrm{H}$ bond angle in $\mathrm{NH}{3}$ is greater than $\mathrm{H}-\mathrm{As}-\mathrm{H}$ bond angle in $\mathrm{AsH}{3}$.
