Question

The correct order of increasing basic nature of the following base is :

• A. 2 < 5 < 1 < 3 < 4
• B. 5 < 2 < 1 < 3 < 4
• C. 2 < 5 < 1 < 4 < 3
• D. 5 < 2 < 1 < 4 < 3

Answer 1

Answer: (A)

2 < 5 < 1 < 3 < 4

In structure 2, electron withdrawing group $N{O}_2$ present in para position.

Also in structure 5, electron withdrawing group $N{O}_2$ is present in meta position.

At para position $N{O}_2$ shows more withdrawing effect than at meta position due to $-R$ effect.

Hence, structure 2 is least basic.

Next basic structure is aniline i.e., structure 1.

Next comes the structure 3 and 4 in which methyl and methoxy groups are present which are electron-donating groups.

So the correct answer is A