Aniline is a derivative of benzene which contains which functional group?

Aniline (C₆H₅NH₂) is one of the simplest and most important aromatic amines in organic chemistry. It is formed when one hydrogen atom of benzene (C₆H₆) is replaced by an amino group (-NH₂). Therefore, the functional group present in aniline is the amino group, making it an aromatic amine.

The amino group (-NH₂) consists of one nitrogen atom bonded to two hydrogen atoms and a lone pair of electrons on nitrogen. This lone pair contributes to the reactivity of aniline, particularly in electrophilic substitution reactions, such as nitration, halogenation, and sulfonation. The amino group donates electron density to the benzene ring through resonance and inductive effects, activating the ring and directing incoming substituents to the ortho and para positions.

Aniline exhibits basic properties because of the presence of the nitrogen atom that can accept protons. However, it is less basic than aliphatic amines because the lone pair on nitrogen is partially delocalized into the aromatic ring, reducing its availability for protonation.

Aniline is an industrially significant compound used in the manufacture of dyes, rubber processing chemicals, pharmaceuticals, and polymers like polyurethane. Its derivatives, such as sulfanilic acid and acetanilide, have wide applications in medicinal and dye industries.

In summary, aniline is an aromatic derivative of benzene containing an amino functional group (-NH₂). This group defines its chemical behavior, making it more reactive than benzene toward substitution reactions and establishing its importance as a fundamental compound in organic chemistry.