The amperometric titration of submillinormal concentrations of hexacyanoferrate (III) with mercury (I) perchlorate

Abstract

Although quite precise under rigidly controlled conditions, the mercury(I) amperometric titration, at a rotating platinum electrode, of submillinormal concentrations of hexacyanoferrate(III) in sodium hydroxide-potassium iodide medium gives results that vary with the concentrations of alkali, iodide and hexacyanoferrate(III). Dependence upon solution composition is small in perchloric acid-potassium thiocyanate medium. In this medium, the titration of 5 × 10^–5 to 10^–3N hexacyanoferrate(III) is precise and accurate to within ±1·5 per cent. The titration of 5 × 10^–6N hexacyanoferrate(III) is precise to about 5 per cent.