Chemistry - CHEMICAL BONDING Question with Solution | TestHub

In NH₃, the individual N–H bond dipoles and the lone pair dipole act in the same direction, reinforcing each other to produce a large net dipole moment.

In NF₃, the highly electronegative fluorine atoms pull electron density away from nitrogen, opposing the lone pair dipole and significantly reducing the net dipole moment.

For options B, C, and D, the first species in each pair is perfectly symmetrical and has a net dipole moment of zero ($\mu =0$), which is less than or equal to the second species. Therefore, the dipole moment of the first species is greater than the second only in pair (A).