45 Explain why m-nitroaniline is a ... [FREE SOLUTION]

Chapter 25: 45 (page 1042)

Explain why m-nitroaniline is a stronger base than p-nitroaniline

Short Answer

Expert verified

In m-nitro aniline, the nitro ( $- N O_{2}$ ) group is electron-withdrawing.

The electron does not get attracted directly by $- N O_{2}$ in m-nitroaniline because no resonance structure is possible with the electron delocalized over $- N O_{2}$ .

Hence, it is a stronger base than p-nitroaniline.

Step by step solution

Basicity of disubstituted aromatic amines

In a disubstituted aromatic amine ring, two factors show a significant effect on basicity

A strong electron-withdrawing group reduce the basicity of nearby amines through inductive effect

When amine is adjacent to the pi acceptor group basicity is affected due to resonance.

Explanation

In m-nitro aniline, the nitro ( $- N O_{2}$ ) group is electron-withdrawing, hence decreasing the basicity of amine.

Resonance structure of m-nitro aniline

The electron does not get attracted directly by $- N O_{2}$ in m-nitroaniline because no resonance structure is possible with electron delocalized over $- N O_{2}$ .

Hence, it is more basic than p-nitroaniline.

In p-nitro aniline, the electron gets attracted directly by $- N O_{2}$ in p-nitroaniline because one additional resonance structure is possible with electron delocalization over $- N O_{2}$ .