Question

How is oxygen have sp2 hybridization in co2?

Answer 1

because in co2 oxygen atom is combined with carbon by double bond. two atoms of oxygen both with double bond. that's why sp2 hybridisation

Answer 2

just as the carbon atom hybridized to form the best bonds, so do the oxygen atoms.To accommodate the two lone pairs and the bonding pair,it will also form 3 equivalent sp2
hybrid.
Hope helps u