Although the amino group (-NH₂) is typically an ortho-para directing group in aromatic electrophilic substitution reactions, a significant amount of meta-nitroaniline is formed during the nitration of aniline. This is because:

a) The amino group loses its directing ability in acidic conditions.
b) The nitrating agent attacks the meta position due to steric hindrance.
c) Aniline is protonated in the acidic medium, forming the anilinium ion (NH₃⁺) , Which is a meta-directing group.
d) The reaction is not selective and attacks all positions equally.