Question:

Nitration of aniline in strong acidic medium also gives m-nitroaniline because _____.

In strong acidic medium aniline is present as anilinium ion

In spite of substituents nitro group always goes to onlym−positions

In electrophilic substitution reactions amino group is meta directive

In absence of substituents nitro group always goes tom−positions

Solution:

The correct option is A. In strong acidic medium aniline is present as anilinium ion.
Nitration of aniline in strong acidic medium also gives m-nitroaniline because in acidic (strong) medium aniline is present as anilinium ion. Amino−NH2 group is ortho-para directing but −NH+3 group is meta directing.
C6H5−NH2 + H+ (strong acid, nitrating mixture) → C6H5−NH+3NO+2 → m−nitroaniline