Explain why aniline in strong acidic medium gives a mixture of Nitro anilines and what steps need to be taken to prepare selectively P - nitro aniline.

Explanation

In strong acidic medium anline under go nitration to form mixture of nitro anilines. In strongly acidic medium aniline is protonated to form the anilinium ion which is metadirecting. So besides the ortho and para derivatives meta derivative also formed.

By protecting - `NH_(2)` group by acetylation reaction with acetic an hydride the nitration reaction can be controlled and the - P - nitro derivative can be formed as major product.