Complexone effects on the kinetics of solution of copper(II) oxide in acid media

The influence of complexones (hydroxyethylenediphosphonic acid, ethylenediaminetetraacetate, and diethylenetriaminepentaacetate) on the kinetics of solution of copper(II) oxide in acid media was studied. The decelerating action of the complexones was found to be related to the formation of surface complexes of copper, which decrease the number of active solution sites on the surface of copper(II) oxide. The products of solution were studied. A mechanism of the inhibiting action of complexones was suggested and given a quantitative description. The mechanism is based on the assumption that the rate-determining step of copper(II) oxide solution in solutions of complexones is transfer of the complexes formed in the reaction from the surface into solution.