Carbon atom in carbonyl is:

Explanation

In a carbonyl, the carbon atom is double-bonded to an oxygen atom and single-bonded to another atom. The oxygen atom is more electronegative than the carbon atom, so it pulls the electrons towards itself and creates a partial positive charge on the carbon atom. To accommodate this charge separation, the carbon atom must be hybridized. Hybridization is the mixing of atomic orbitals to form hybrid orbitals that have different shapes and energies from the atomic orbitals. The carbon atom in a carbonyl forms three sigma bonds in the molecule, and one pi bond with the oxygen atom. In SP2 hybridization, the carbon atom uses one S orbital and two P orbitals to form three hybrid orbitals that are arranged in a trigonal planar geometry. The remaining P orbital of carbon overlaps with the P orbital of oxygen to form the pi bond. Therefore, the carbon atom in a carbonyl is SP2 hybridized.