Caustic soda

Like chlorine, caustic soda is produced in the chloralkaline process and has a range of uses such as the production of organic and inorganic chemicals, bleaching in the pulp and paper industry and as an active ingredient in soaps and detergents.

Due to their hardness, corrosion resistance, high melting point and high temperature stability ruthenium and iridium can be used to coat the cathode and anode respectively in the chloralkaline process where aqueous sodium chloride (saltwater) is electrolysed. Chlorine gas is released at the anode and the cathode reduces water to hydrogen, leaving sodium hydroxide, better known as caustic soda.