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

The reason for formation of an unexpected amount of m -nitroaniline is that under strongly acidic condition of nitration, most of the aniline is converted into anilinium ion and since, -N+H3 .Due to strong -I effect,very little ortho product(2%) and   a large amount of m -nitroaniline(47%) and para nitro aniline (51%) are  obtained.