After a discussion about the structures of hydrides of group-15 elements, .Neethu wrote the order of bond angles as `NH_3ltPH_3ltAsH_3`. Justify ‘your answer:

Explanation

The bond angle decreases from `NH_3`to `BiH_3`,i.e., the correct order of bond’ angle is `NH_3gtPH_3gtAsH_3`.As the size of the central atom in the hydride increases, its electronegativity. decreases, Consequently the position of the bond pair of electrons tend to lie away from the central atom in moving from `NH_3` to `AsH_3` As a result the repulsion between bond pair of electrons' ' decreases and the bond angle decreases.