Question

The which of the species all the carbon atom are sp2 hybrid state

Answer 1

Assuming all atoms are hybridized, the carbon and oxygen atoms are sp2 hybridized, and the two chlorine atoms are sp3 hybridized. The two C‒Cl σ bonds are formed from overlap of sp2 hybrids from C with sp3 hybrid orbitals from Cl. The double bond between the carbon and oxygen atoms consists of one σ and one π bond.