Castner-Kellner cell is used for the production of

Caustic soda or sodium hydroxide (NaOH) are produced using the Castner-Kellner method.

The electrolysis of brine, a highly concentrated solution of sodium chloride in the presence of mercury electrodes, is the first stage in the procedure. As a result of electrolysis, the chlorine which is evolved at the anodes is evacuated from the chamber and the positively charged sodium ions are reduced and deposited at the mercury electrodes to create an amalgam.