Question

Which among the following molecule is not a dipole?

(a) NH3

(b) H2O

(c) HCl

(d) CH4

The question was posed to me during a job interview.

This key question is from Electric Dipole in chapter Charges and Fields of Physics – Class 12

Answer 1

Right answer is (d) CH4

For explanation I would say: Though water and ammonia are covalent molecules, they have a net dipole moment due to their distorted structure than the ideal one. Hydrochloric acid has a linear molecular structure but its net dipole moment is towards the Hydrogen atom. But methane has a symmetrical tetrahedral structure and its net dipole moment is zero hence it doesn’t behave as a permanent dipole. Methane solvents are therefore non-polar solvents.