Inter-Comparison Potentials of Ag / AgCI Electrodes in Aqueous Solution

The inter-comparison potentials of Ag/ AgCl electrodes in aqueous HCl solutions of different concentrations prepared by a number of different methods, have been measured at room temperature. It has been found that among different electrodes prepared by the same method, the inter-comparison potentials are quite low (0.05 mV for thermo-electrolytic, 0.2 mV for electrolytic electrodes); though that between the electrodes prepared differently is rather high. The E° value of one thermo-electrolytic electrode obtained from E.M.F. measurements in the cell : H₂ /HCI (m) AgCI/Ag, and suitable extrapolation, has been found to be +0.2225V at 26.5°C.