Question

Which of the Following molecules has net dipole moment zero?
(a)HF.
(b)H20.
(c)NH2.
(d)PCl3​

Answer 1

Answer:

All the three molecules methane, carbon tetrabromide and acetylene have zero dipole moments as the individual bond dipoles cancel each other which result in zero net dipole moments.

Answer 2

Answer:

None of the following molecules has net dipole moment zero

Explanation:

$HF$ has a dipole moment due to the difference in electronegativity between hydrogen and fluorine

$H_{2} O$ is an example of a polar molecule and it has a non zero dipole moment

$NH_{3}$ has three bonds in a single plane so the dipole moment does not cancel each other. Therefore it has a non-zero dipole moment.

$PCl_{3}$ has a lone pair so the dipole moment of lone-pair and bond-pair do not cancel each other.