In a corrosion cell, which of the following is NOT required?

In a corrosion cell, the presence of an electrolyte, electrons, and current is essential for the electrochemical reactions that cause corrosion to occur.

The electrolyte is crucial because it facilitates the movement of ions between the anode and cathode, allowing the corrosion process to take place. Electrons are produced at the anode during oxidation reactions and must travel to the cathode for reduction reactions to occur, forming a continuous circuit that sustains the corrosion process. Current is likewise necessary as it is the result of the flow of electrons, representing the ongoing electrochemical reactions.

Oxygen, while it can play a role in some types of corrosion—particularly in aerobic environments—is not an absolute requirement for the corrosion cell to function. There are instances of anaerobic corrosion where conditions allow for corrosion to occur without the presence of oxygen. Therefore, stating that oxygen is not a requirement is accurate, highlighting that it can influence but is not essential in every corrosion cell scenario.