Q. The conect order of $H - N - H$ bond angles of ammonia, ammonium ion and amide are
TS EAMCET 2020
Solution:
According to VSEPR theory repulsion between :
Lone pair-lone pair $>$ Lone pair-bond pair $>$ Bond pair-bond pair
As the repulsion is increases then bond angle is decreases.
Molecule
Lone pair
Bond pair
Bond angle
$NH _{2}{ }^{-}$
2
2
$105^{\circ}$
$NH _{3}$
1
3
$107^{\circ}$
$NH _{4}^{+}$
0
4
$109^{\circ} 28'$
Therefore, the order of bond angle is $NH _{4}^{+}> NH _{3}> NH _{2}^{-}$
| Molecule | Lone pair | Bond pair | Bond angle |
|---|---|---|---|
| $NH _{2}{ }^{-}$ | 2 | 2 | $105^{\circ}$ |
| $NH _{3}$ | 1 | 3 | $107^{\circ}$ |
| $NH _{4}^{+}$ | 0 | 4 | $109^{\circ} 28'$ |