Question

How many more resonating structures does aniline have than anilinium ion?

(a) 2

(b) 3

(c) 4

(d) 5

I had been asked this question in examination.

The question is from Amines Chemical Reactions in portion Amines of Chemistry – Class 12

Answer 1

Right choice is (b) 3

To explain I would say: Aniline has five resonating structures, out of which three of them have a positive charge on nitrogen. This results in unavailability of electron pair for protonation. When aniline accepts a proton, it forms anilinium ion which has only two resonating structures and is less stable and more basic than aniline.