The powder electrode potentials using manganese dioxide, prepared under different conditions, as the powder phase have been measured in presence of different concentrations of reference electrolyte solu­tions. Parallel studies on surface areas of the powders, adsorption property, catalytic activity in the de­composition of hydrogen peroxide, have also been made with the object of drawing possible qualitative correlations between powder potentials of the different varieties on the one hand and specific surface areas, energies of activation etc on the other. Similarities exist in the sequence of increase in the powder poten­tials of the different samples and the sequence of increase or decrease of specific surface areas of the powders and of energies and entropies of activation.