METHOD FOR ELECTROLYZING ALKALI CHLORIDE

PROBLEM TO BE SOLVED: To provide a method for preventing the deterioration of electrolytic performance with time to the utmost at the time of electrolyzing an aqueous alkali chloride solution mixed with recovered hydrochloric acid by an ion- exchange membrane process and/or an aqueous solution of by-produced alkali chloride recovered from a reaction solution subjected to the dehydrochlorination reaction of an organochlorine compound by detecting an index of organic impurity concentration in an aqueous alkali chloride solution correlated to the deterioration of electrolytic performance with time and imparting the tolerance indicated by the index. SOLUTION: The organic impurity concentration, expressed in terms of tetrachlorobutane, quantitatively analyzed by ECD-GC in the aqueous alkali chloride solution is controlled to