Question

Basicity order of the following amines in aqueous medium
i) N-Methylaniline i
i) N, N-Dimethylaniline 
iii) Aniline

• A. i $\displaystyle >$ ii $\displaystyle >$ iii
• B. i $\displaystyle >$ iii $\displaystyle >$ ii
• C. iii $\displaystyle >$ ii $\displaystyle >$ i
• D. ii $\displaystyle >$ i $\displaystyle >$ iii

Hint:

In amines, basicity increases with the electron-donating ability of the substituent on the nitrogen atom.

Answer 1

The Correct Option is D

In aqueous medium, the electron-donating groups (such as alkyl groups) attached to the nitrogen atom increase the basicity of the amine. 
In this case, N, N-Dimethylaniline (ii) has the highest basicity, followed by N-Methylaniline (i), and Aniline (iii) with the lowest basicity. 
The presence of two methyl groups on the nitrogen in N, N-Dimethylaniline makes it more basic than N-Methylaniline, which has only one methyl group. Aniline has the least basicity due to the lack of any alkyl groups on the nitrogen.