When Harrison Wells and Caitlin Snow are discussing how to improve Harrison's speed-enhancing formula, Caitlin proposes a chemical compound to provide oxygen: sodium chloride. Sodium chloride is ordinary table salt. It consists only of the elements sodium and chloride, no oxygen. There is no way adding this to Harrison's formula could provide oxygen.
Actually, Caitlin Snow didn't say Sodium Chloride, that is NaCl without any Oxygen. She actually said Sodium Chlorate, NaClO3, which does have Oxygen, so it can decompose to give Sodium Na, Chloride Cl, and Oxygen O2. It is a smart choice because it has 3 times Oxygen than it has Sodium or chloride.