Question

Which of the following molecules has the maximum dipole moment?

• A. $C{O}_2$
• B. $C{H}_4$
• C. $N{H}_3$
• D. $N{F}_3$

Answer 1

Answer: (C)

$C{O}_2$ and $C{H}_4$ have zero dipole moment as these are symmetrical in nature. Between $N{H}_3$ and $N{F}_3$, $N{F}_3$ has greater dipole moment though in $N{H}_3$ and $N{F}_3$ both, $N$ possesses one lone pair of electrons.
This is because in case of $N{H}_3$, the net $N-H$ bond dipole is in the same direction as the direction of dipole of lone pair but in case of $N{F}_3$, the direction of net bond dipole of three $-N-F$ bonds is opposite than that of the dipole of the then lone pair.