Question

Give reasons for the following:

CH₃NH₂ is more basis than C₆H₅NH₂.

Answer 1

Aromatic amines are far less basic than aliphatic amines. This can be explained as follows:

Resonance stabilisation is there in aniline. It can be regarded as a resonance hybrid of the following structures:

Hence, the lone pair of electrons on the nitrogen atom gets delocalised over benzene ring and thus is less available for protonation.

The electron density on the nitrogen atom is increased by electron-donating inductive effect of the alkyl groups. As a result, aliphatic amines are much stronger bases than aniline.