Applications involving iodide and persulphate: use of persulphate and iodide in the potentiometric determination of arsenite, phosphite, hypophosphite and quinol

ABSTRACT

A new reliable potentiometric method is given for the determination of persulphate based on reduction with iodide and titration of unreacted iodide with Hg [II] using silver amalgam as the indicator electrode in conjunction with a standard calomel electrode over a wide range of concentrations. The end point potential breaks amounted to 365-440 mV per 0.1 ml titrant and hence the high accuracy of the present method. Rapid and accurate potentiometric methods have been developed for estimation of arsenite, phosphite, hypophosphite and quinol based on oxidation with persulphate and subsequent determination of unreacted pxidant potentiometrically as mentioned above. The results are quite satisfactory and the end points are well defined with very sharp potential breaks ranging from 200 to 398 mV per 0.1 ml of mercury [II]