Answer:
6 moles of oxygen, or 3O2.
Explanation:
I would build a proportion for this:

electrons are transferred in a oxidation-reduction reaction
oxidation reduction chemical equation involve electrons transfer between two species. In this reduction-oxidation type of chemical equation oxidation number of molecule, atoms or ion changes by gaining or losing electrons,that is there an oxidizing agent and a reducing agent in the reaction.
CaCl2 is a good conductor of electricity when dissolved in water.