Critical thinking problem: Acetylene torches, which are used in welding, burn at over 3200°C. Acetylene reacts with dioxygen to form two carbon dioxide molecules and also water. What are the hybridization orbitals of the carbons in acetylene?

What is the hybridization orbital for the carbon in carbon dioxide?

The oxygen in O2 has hybridization of sp2, while in H2O it is sp3. Since these are the same oxygen atoms, how could there be a change from one hybridization orbital to the other?