Zinc dissolution in Leclanche electrolyte

Abstract

The rate and morphology of zinc dissolution were studied in a Leclanche electrolyte of composition 0.5 mol dm^-3 ZnCl₂ and 5 mol dm^-3 NH₄Cl. A gelled electrolyte layer 2 x 10^-3 m thick on the zinc surface was found to reduce the corrosion rate by an order of magnitude and to promote even dissolution. The corrosion results are interpreted in terms of a diffusion-controlled cathodic reaction involving O₂ dissolution and metallic impurity deposition.