Question

The electronegativity difference between $N$ and $F$ is greater than that between $N$ and $H_4$ yet the dipole moment of $N{H}_3$ (1.5 D) is larger than that of $N{F}_3$ (0.2 D). This is because :-

• A. in $N{H}_3$ as well as in $N{F}_3$, the atomic dipole and bond dipole are in the same direction
• B. in $N{H}_3$, the atomic dipole and bond dipole are in the same direction whereas in $N{F}_3$ these are in opposite directions
• C. in $N{H}_3$ as well as $N{F}_3$, the atomic dipole and bond dipole are in opposite directions
• D. in $N{H}_3$ the atomic dipole and bond dipole are in the opposite directions whereas in $N{F}_3$ these are in the same directions

Answer 1

Answer: (B)

Electronegativity of N is greater than that of H, but in $N{F}_3$ electronegativity of F is greater than that of N. So, in $N{H}_3$ the atomic dipole and bond dipole are in the same direction whereas in $N{F}_3$ these are in opposite direction.