The amines which are less basic than aniline are:

A. p-Toluidine

B. 4-Methoxybenzamine

C. 4-Aminobenzoic acid 

D. 4-Nitrobenzamine 

E. 4-Chlorobenzamine 

Choose the correct answer from the options given below:

C, D, E only

The correct answer is option 3. C, D, E only.

The basicity of an amine is determined by its ability to donate a lone pair of electrons from the nitrogen atom to an acid (proton). The presence of substituents on the aromatic ring can influence this ability:

Electron-Donating Groups: Increase the electron density on the nitrogen atom, making it more available for donation, thus increasing basicity.

Electron-Withdrawing Groups: Decrease the electron density on the nitrogen atom, making it less available for donation, thus decreasing basicity.

Aniline has a nitrogen atom bonded to a benzene ring. In aniline, the lone pair of electrons on the nitrogen is partially delocalized into the aromatic ring, reducing the electron density available for protonation compared to aliphatic amines. This makes aniline less basic than aliphatic amines but still a standard reference for aromatic amines.

Evaluation of Each Derivative:

A. p-Toluidine (A):

Substituent: Methyl group (CH₃).

Effect: The methyl group is an electron-donating group through its +I effect. It increases the electron density on the nitrogen atom.

Basicity: More basic than aniline due to increased electron density on the nitrogen.

B. 4-Methoxybenzamine:

Substituent: Methoxy group (OCH₃).

Basicity: More basic than aniline because it significantly increases the electron density on the nitrogen.

C. 4-Aminobenzoic Acid :

Substituent: Carboxyl group (COOH).

Effect: The carboxyl group is a strong electron-withdrawing group through its -M (resonance) and -I (inductive) effects.

Basicity: Less basic than aniline because it pulls electron density away from the nitrogen, making it less available to donate its lone pair.

D. 4-Nitrobenzamine :

Substituent: Nitro group (NO₂).

Effect: The nitro group is a very strong electron-withdrawing group through its -M (resonance) and -I (inductive) effects.

Basicity: Less basic than aniline due to the significant withdrawal of electron density from the nitrogen.

E. 4-Chlorobenzamine:

Substituent: Chloro group (Cl).

Effect: The chloro group is a weak electron-withdrawing group through its -I (inductive) effect, though not as strong as nitro or carboxyl groups.

Basicity: Less basic than aniline due to the slight withdrawal of electron density from the nitrogen.

Conclusion

Less Basic Than Aniline: 4-Aminobenzoic Acid (C), 4-Nitrobenzamine (D), and 4-Chlorobenzamine (E) have electron-withdrawing groups that reduce the electron density on the nitrogen and make them less basic.

More Basic Than Aniline: p-Toluidine (A) and 4-Methoxybenzamine (B) have electron-donating groups that increase the electron density on the nitrogen, making them more basic than aniline.

Thus, the correct answer is 3. C, D, E only.