Kinetic regularities pertaining to electroreduction of compounds of hexavalent chromium (1 M CrO3) to the trivalent state are investigated on the gold electrode. It is shown that this reaction proceeds by the CE mechanism. The chemical step, preceding the discharge, involves some compounds (H2SO4, HCOOH, HF, HCl, etc.) that accelerate reduction of Cr(VI). They are incorporated into electroactive surface compounds (substituted polychromates) and carry out electron transfer by the bridge mechanism