The chloralkali process (also chlor-alkali and chlor alkali) is an industrial process for the electrolysis of NaCl . It is the technology used to produce chlorine and sodium hydroxide (caustic soda), which are commodity chemicals required by industry. 35 million tons of chlorine were prepared by this process in 1987. Industrial scale production began in 1892.Usually the process is conducted on a brine (an aqueous solution of NaCl), in which case NaOH, hydrogen, and chlorine result.