When aniline is treated with a mixture of concentrated and (direct nitration), a surprisingly large amount of meta-nitroaniline (approx. 47%) is formed alongside the expected ortho and para isomers. W

Question

When aniline is treated with a mixture of concentrated $HNO_3$ and $H_2SO_4$ (direct nitration), a surprisingly large amount of meta-nitroaniline (approx. 47%) is formed alongside the expected ortho and para isomers. Which of the following statements correctly explains this phenomenon?

Prashant Kotian · Accepted Answer

Correct answer: B,C. The free amino group is a strong ortho/para director. However, in the highly acidic nitrating mixture, the basic amino group accepts a proton to form the anilinium ion (). The anilinium ion has a full positive charge on nitrogen and no free lone pairs for resonance, exerting a powerful effect. This makes it strongly deactivating and meta-directing, leading to the large yield of the meta isomer.

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