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Q.
When $NH _{3}$ accepts a proton in aqueous solution
Chemical Bonding and Molecular Structure
Solution:
$NH _{3}$ is in $s p^{3}$ hybridised state with one lone pair. Due to the repulsion of lone pair-bond pair, the bond angle of ammonia is lower than $109^{\circ} 28^{\prime}$.
When this lone pair is donated to $H ^{+}$, the lone pair-bond pair repulsion diminishes and bond angle increase to $109.5^{\circ}$ without affecting hybridisation or $s$ -character.
