Why is an alkali added to the cathode of an electrolyzer?

What are the products at the cathode of electrolyzing saltwater? Once you understand the equation, you’ll know

Increasing the ion concentration in the catholyte improves electrolysis efficiency

The cathode alkali cycle is intended to control the tank temperature and has no relation to anything else.

Increase the conductivity of the clitoral fluid, improve the purity of the alkaline solution, and enhance the quality of the alkaline solution

This requires considering the electrochemical reactions in the electrolysis process as well as maintaining a high efficiency for that process. The cathode of a chlor-alkali electrolyzer is where hydrogen ions in water are electrolyzed to produce hydrogen gas; as a result, hydroxide ions remain in the water. Sodium ions, attracted to the cathode, pass through the cation exchange membrane into the cathode chamber, thereby forming sodium hydroxide in the catholyte. In the initial stage of electrolysis, adding pure water can also yield sodium hydroxide through electrolysis; however, due to the high resistivity of pure water, this leads to an increase in cell voltage, reduced current efficiency, and higher power consumption. By increasing the conductivity of the catholyte and thus improving its electrical conductivity, the problems of reducing the cell voltage and enhancing electrolysis efficiency can be solved. Therefore, using a sodium hydroxide solution at a certain concentration as the catholyte allows for an increase in its conductivity without the introduction of other impurity ions, which in turn improves the electrolysis efficiency. The original poster should go and read carefully books on the principles of the ion-exchange membrane caustic soda production process.