This International Standard specifies a photometric method for the determination of the chlorides content of sodium hydroxide for industrial use.
The method is applicable to products having chloride contents, expressed as chlorine (CI), between 2 mg/kg and 50 mg/kg.
NOTE —For contents exceeding 50 mg/kg, use the method specified in ISO 981, Sodium hydroxide for industrial use —Determination of chlorides content —Mercurimetric method, or reduce the volume of the test solution according to the note in 7.4.3.