Why a NaCl salt solution containing dissolved oxygen will be more corrosive than an air free salt solution)?

A NaCl salt solution containing dissolved oxygen is more corrosive than an air-free salt solution because the presence of oxygen facilitates electrochemical reactions that lead to corrosion. Oxygen acts as an oxidizing agent, promoting the oxidation of metal surfaces and increasing the rate of corrosion processes, such as pitting and rusting. In contrast, an air-free solution lacks dissolved oxygen, which limits these electrochemical reactions and reduces the overall corrosive potential. Hence, the combination of salt and dissolved oxygen significantly enhances the corrosive environment.