Fig. 9 Comparison of the prediction of the "independent adsorption" reaction mechanism with the experimental data at 25°C shown both on a linear scale (a) and on a logarithmic scale (b). The best fit curve adequately describes the experimental data. The mathematical predictions of the "independent adsorption" and the "perchlorate adsorption onto the adsorbed proton" reaction mechanisms are identical and therefore each of these mechanisms is a viable explanation for the experimental results.