Question

Arrange the following:

In increasing order of basic strength:

Aniline, p-nitroaniline and p-toluidine

Answer 1

In p-toluidine, the presence of an electron-donating −CH₃ group increases the electron density on the N-atom. Thus, p-toluidine is more basic than aniline.

On the other hand, the presence of electron-withdrawing −NO₂ group decreases the electron density over the N-atom in p-nitroaniline. Thus, p-nitroaniline is less basic than aniline.

Hence, the increasing order of the basic strengths of the given compounds is as follows:

p-Nitroaniline < Aniline < p-Toluidine