Question

In a resonant hybrid of a molecule like CH3CO2-, how are the electron orbitals of the carbon in CO2 sp hybridized?

Answer 1

you need to have a reasonable Lewis structure for a molecule before you can really predict anything about the hybridization of its orbitals. Can you do that?

Answer 2

In any carboxylic acid anion, the carbon is sp2 hybridized, forming one sigma bond with each oxygen, one sigma bond with the carbon backbone, and using the leftover p orbital to participate in pi bonding with both oxygens.

Answer 3

This would be the lewis structure.