The hybridization of nitrogen in an amine is

Explanation

In a primary amine, such as CH3NH2, the nitrogen atom forms three sigma bonds with three hydrogen atoms and one sigma bond with a carbon atom. To form these four bonds and the lone pair, the nitrogen atom in primary amines undergoes SP3 hybridization. This means that one 2s orbital and three 2p orbitals of the nitrogen atom combine to form four SP3 hybrid orbitals, which are arranged in a tetrahedral geometry around the nitrogen atom. In a secondary amine, such as (CH3)2NH, the nitrogen atom forms two sigma bonds with two alkyl groups and two sigma bonds with two hydrogen atoms. To form these four bonds and the lone pair, the nitrogen atom in secondary amines undergoes SP3 hybridization. This means that one 2s orbital and three 2p orbitals of the nitrogen atom combine to form four SP3 hybrid orbitals, which are arranged in a tetrahedral geometry around the nitrogen atom. In a tertiary amine, such as (CH3)3N, the nitrogen atom forms three sigma bonds with three alkyl groups. To form these three bonds and the lone pair, the nitrogen atom in tertiary amines undergoes SP3 hybridization. This means that one 2s orbital and three 2p orbitals of the nitrogen atom combine to form four SP3 hybrid orbitals, which are arranged in a trigonal pyramidal geometry around the nitrogen atom. If the nitrogen atom in an amine is part of a planar aromatic ring, such as in aniline, it undergoes SP2 hybridization. This is because the nitrogen atom forms three sigma bonds with three carbon atoms in the ring and has one unhybridized p orbital, which participates in pi bonding with the aromatic ring. This means that one 2s orbital and two 2p orbitals of the nitrogen atom combine to form three SP2 hybrid orbitals, which are arranged in a planar triangular geometry around the nitrogen atom.