Question

Assertion : Dipole moment of $N{H}_3$ is greater than that of $N{F}_3$.
Reason : Nitrogen is more electronegative than fluorine.

• A. If both assertion and reason are true and reason is the correct explanation of assertion
• B. If both assertion and reason are true but reason is not the correct explanation of assertion
• C. If assertion is true but reason is false
• D. If both assertion and reason are false

Answer 1

Answer: (C)

In case of $N{H}_3$, the orbital dipole due to lone pair is in the same direction as the resultant dipole moment of the three $N-H$ bonds whereas in $N{F}_3$ the orbital dipole is in the direction opposite to the resultant dipole moment of three $N—F$ bonds which decreases the dipole moment of $N{F}_3$ as shown below: