Question

Among the following amines, which one has the highest $p{K}_b$ value in aqueous solution?

• A. Methanamine
• B. N, N-dimethylaniline
• C. Ethanamine
• D. Benzenamine
• E. None of the above

Answer 1

The correct option is D Benzenamine

+Inductive effct increases the electron density on nitrogen thus makes it more basic while +R effect involves the lone pair of N in conjugation thereby reduces its basicity.

Therefore aniline are less basic than alkyl amines and secondary aniline are more basic than aniline.

Highest $p{K}_b$ means least basic nature, therefore option D is correct.