Tin (II)-Strong Phosphoric Acid. A New Reagent for the Determination of Sulfate by Reduction to Hydrogen Sulfide

Abstract

Abstract A new reagent, “ Tin(II)-Strong Phosphoric Acid ”, has been prepared to permit a rapid and simple determination of sulfates by reducing to hydrogen sulfide. The reagent is stable at a room temperature but reacts-violently above 120°C. Evolved hydrogen sulfide after the reaction with this reagent is absorbed in zinc acetate-acetic acid solution and titrated iodometrically as usual. 1 ml of 0.02n iodine solution corresponds to 0.9607 mg. of sulfate ion. The apparatus for the preparation of the reagent and reduction of sulfate are illustrated. The determination of sulfur in various sulfates was carried out by this method and satisfactory results were obtained. Moreover, it seems to be an advantage of this method that solid samples can be treated directly in the reaction vessel. The expense of the present research has been paid in part by a Grant for Scientific Research from the Ministry of Education.