Question

Although F is more electronegative than H, the resultant dipole moment of $N{H}_3$ is much more than that of $N{F}_3$. It can be explained as:

• A. the lone pair of nitrogen opposes the dipole moment of $N{F}_3$ while it is added to the dipole moment of $N{H}_3$
• B. all the dipoles of $N{F}_3$ are in same direction
• C. all the dipoles of $N{H}_3$ are in opposite direction
• D. $N{H}_3$ has a regular geometry while $N{F}_3$ has irregular geometry which makes dipole moment of $N{H}_3$ more than $N{F}_3$

Answer 1

The correct option is A the lone pair of nitrogen opposes the dipole moment of $N{F}_3$ while it is added to the dipole moment of $N{H}_3$

In $N{H}_3$

Hydrogen is less electronegative than nitrogen so all the electron will move towards nitrogen, due to this all the vectors will be in the same direction and the summation will come maximum.

In $N{F}_3$

Fluorine is more electronegative than nitrogen so all the electron will move towards fluorine, due to this all of the vectors will cancel each other and the summation will come minimum.