Utilization of hydralazine hydrochloride in the Potentiometric Determination of Osmium(VIII): Analysis of Binary and Ternary Mixtures

A simple, rapid and accurate potentiolnetric method is described for tlie
determination of Os(VIII) in tlie co~icentrationr ange 0.4-4.0 mg/ml. Tlie method is
based on tlie addition of hydralazine hydrochloride to Os(VIII) to reduce it to Os
(IV). The excess of hydralazine hydrocliloridew as oxidized by iodine dissolved ill acetic acid. The liberated iodide was then potentiometrically titrated against mercury(II) using silver amalgam as the indicator electrode. The potential of this method for sime- microdetermination is important in practical applications where tlie above reaction should proceed quantitatively towards completion. The relative standard deviation for six replicate deterinination of osmium(VIII) in binary and
ternary mixtures without the need for extraction or heating.