ISO 3236:1975

Sodium sulphate for industrial use — Determination of chlorides content — Mercurimetric method

Applicable to products the content of which expressed as chlorine exceeds 0.005 % (m/m). If the analyst can easily detect the indicator’s colour change using a 0.02 N standard volumetric mercury(II) nitrate solution the method can, subjected to agreement, be extended to products the content of which exceeds 0.001 % (m/m). The titration of the chloride ions (Cl- ) is carried out with a 0.1 N standard volumetric solution of mercury(II) nitrate in the presence of 1,5-diphenylcarbazone as indicator.