The correct option is
A 1
Hydride | NH3 | PH3 | AsH3 | SbH3 |
H-M-H angle | 107 | 92 | 91 | 90 |
This variation in bond angle can be explained on the basis of electronegativity of the central atom.
- Since nitrogen atom is highly electronegative. So in NH3 there is high electron density around the N atom which causes greater repulsions between the electron pairs around the N atom resulting in maximum bond angle.
- Since electronegativity decreases down the group, the electron density also decreases and consequently the repulsive interactions between the electron pairs also decrease thereby decreasing the bond angle H-M-H.