If the dipole moment of toluene and nitro-benzene are 0.43 D and 3.93 D respectively, then the expected dipole moment of p-nitrotoluene will be.

Options

A. 3.50 D
B. 2.18 D
C. 4.36 D
D. 5.30 D

Answer

C

Explanation

Methyl group has +1 effect and `-NO_2` group has -I effect. Therefore, in p-nitrotoluene, the dipole moments of `-CH_3` and `-NO_2` groups act in the same direction. So, the resultant dipole moment is additive.
i.e., `3.93 + 0.43 = 4.36 D`