Method of operating an electrolytic cell

In a method of operating an electrolytic cell having an anolyte compartment with an anode therein, a catholyte compartment with a cathode therein, wherein the cathode has a low hydrogen overvoltage surface thereon, and the catholyte compartment has exposed iron therein, the low hydrogen overvoltage surface having a lower hydrogen overvoltage than the exposed iron, which method comprises feeding alkali metal chloride brine to the anolyte compartment, passing an electrical current from the anode to the cathode, and recovering an aqueous alkali metal hydroxide catholyte containing iron as an impurity, the improvement comprising adding an iron corrosion inhibiting amount of a composition comprising alkali metal benzoate and alkali metal nitrite to the catholyte compartment during electrolysis.