How many molecules among the following have zero dipole moment `NH_(3),BF_(3),NF_(3),C CI_(4)` ? .

Answer

2

Explanation

`overset(..)NH_(3) implies sp^(3)` hybridised `implies `pyramidal `implies mu ne 0`
(ii) `BF_(3) implies sp^(2)` hybridised` implies `planar and symmetrical `implies mu =0`
(iii) `overset(..)NF_(3) implies sp^(3)` hybridised `implies` pyramidal `implies mu ne 0`
(iv) `C CI_(4) implies sp^(3)` hybridised` implies `TH and symmetrical ` implies mu =0`
Hence `BF_(3)` and `C CI_(4)` have zero dipole moment .