What happens to the pH of the environment around the cathode during cathodic protection?

During cathodic protection, cathodic polarization occurs at the cathode, which leads to the reduction of hydrogen ions in the solution. This reduction results in the consumption of hydrogen ions, which decreases the concentration of these ions in the vicinity of the cathode. Consequently, as the concentration of hydrogen ions decreases, the pH of the environment around the cathode increases, causing the environment to become more alkaline.

This phenomenon is a direct result of the electrochemical reactions taking place during cathodic protection, specifically during processes such as the reduction of dissolved oxygen or the electrolysis of water. The increase in pH can help to reduce corrosion rates in metal structures under protection because alkaline environments generally decrease the solubility of certain corrosion products, making protective passive films more stable.

Therefore, the correct conclusion is that the pH of the environment around the cathode becomes more alkaline during cathodic protection.