Question

Consider the following species when answering the following question:

(i) NF3
(ii) BF3
(iii) IF3
(iv) PBr3
(v) BrCl3
Of the molecules below, only ________ is nonpolar.
BF3
NF3
PBr3
BrCl3
IF3

Answer 1

Only BF₃ is non polar.

Step-by-step explanation:

The non polar molecule is one which will have zero dipole moment.

This zero dipole moment is possble if

a) the bonds are non polar (completely) and there is no lone electrons

b) the bonds are polar but the overall dipole moment cancel each other due to planar geometry of molecule

i) BF₃ : This is trigonal planar molecule. The overall dipole moment is zero due to symmetric distribution of electrons and thus dipole cancel each other.

ii) NF₃ : there is lone pair of electron and the bonds are polar.

iii) PBr₃: Again presence of lone pair of electrons and thus ssymmetric distribution of electrons

iv) BrCl₃ : The bonds are polar and molecule is not planar.

v) IF₃ : bonds are polar.