A new method for the potentiometric determination of lead with alkaline permanganate

A new method for the estimation of lead, based on its oxidation from the bivalent to the quadrivalent state by alkaline permanganate has been devised. The reaction takes place so rapidly in the presence of a mixture of ZnO and HgO that it can be followed potentiometrically. Oxidation of sodium plumbite with KMn0₄ leads to the formation of PbO and MnO. Reduction of KMnO4 with Pb⁺² ions or with sodium plumbite proceeds almost quantitatively in 2.5N NaOH in the absence of Ba⁺² ions and in 1–1.5N NaOH in the presence of these ions. Under these conditions Pb⁺² Pb⁺¹ and Mn0₄ MnO₄^-2, provided that the lead solution is not added too rapidly.