MECHANISMS GIVING RISE TO POTENTIALS OF ZERO CHARGE IN THE REGION OF IRREVERSIBLE STATES OF PT HCL AND PT/H2SO4 INTERFACES/

The hardness (after Rebinder) vs. potential curves, which are nonequil ibrium analogues of the electrocapillary curves, are acquired on the p latinum electrode in an atmosphere of air and chlorine with sulfuric a nd hydrochloric acids of various concentrations as the background. The surface activity of electrolytes and chlorine is elucidated. The syst ems are traced, and the corresponding conditions are found, in which t he electrocapillary behavior of platinum is governed by either the irr eversible oxygen chemisorption, the oxygen evolution reaction, or the chlorine evolution reaction. The outcome is interpreted on the basis o f the adsorption equation for the irreversible electrode and the notio ns representing the charges as the Gibbs adsorptions of charge-determi ning species.