Question

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

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

Answer 1

The correct option is D 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


In $N{H}_3$ all the dipoles are oriented at the same direction and hence the dipoles are added to give net larger dipole moment. In$N{F}_3$ the dipoles are oriented away from each other and hence cancel each other to give lesser dipole moment.