Although geometries of `NH_(3) and H_(2)O` molecules are distorted tetrahedral, bond angle in water is less than that of ammonia. Discuss.

Explanation

The difference in the bond angles of water `(H_(2)O)` and ammonia `(NH_(3))` is due to difference in the number of lone pairs and bond pairs in these two species. In `NH_(3)`, N has 1 lone pair and 3 bond pairs while in `H_(2)O,` O and 2 lone pairs and 2 bond pairs. the lone pair-bond pairr repulsion in `H_(2)O` is much more than those in `NH_(3)`. hence, bond angle around the central atom in `H_(2)O` is relatively smaler than that in `NH_(3)`.