Decreasing order of basicity for the following compounds:

(A) Ethylamine
(B) Diethylamine
(C) Ammonia
(D) Benzenamine

Choose the correct answer from the options given below:

(B), (A), (C), (D)

The correct answer is Option (3) → (B), (A), (C), (D)

Basicity depends on availability of lone pair on nitrogen.

Electron donating alkyl groups increase basicity. Resonance delocalization decreases basicity.

Detailed Explanation

Option A: Ethylamine

Primary amine with one alkyl group.

Shows +I effect but less than diethylamine.

Hence second.

Option B: Diethylamine

It is a secondary amine.

Two ethyl groups donate electron density via +I effect.

This increases availability of lone pair.

Hence most basic.

Option C: Ammonia

No alkyl group.

No +I effect.

So less basic than alkyl amines.

Option D: Benzenamine

Lone pair is delocalized into benzene ring via resonance.

Thus less available for protonation.

Hence least basic.