Assertion (A): NH₃ and NF₃ molecules have pyramidal shape with a lone pair of electrons on nitrogen atom. The resultant dipole moment of NH₃ is greater than that of NF₃.

Reason (R): In NH₃, the orbital dipole due to lone pair is in the same direction as the resultant dipole moment of the N–H bonds. Fluorine is the most electronegative element.

In the light of the above statements, choose the correct answer from the options given below.

Correct Answer: Both (A) and (R) are true and (R) is the correct explanation of (A).

In NH₃, the dipole moment due to lone pair and the N–H bond dipoles act in the same direction, hence the net dipole moment increases.

In NF₃, due to high electronegativity of fluorine, the N–F bond dipoles act opposite to the lone pair dipole, leading to partial cancellation and smaller net dipole moment.