For the first time, use of a novel pre-conditioning sequence and measurements of hydrogen blockage during fast cathodic scans has enabled the determination of rates of accumulation of ethanolic species on the surface of a platinum electrode under well-controlled conditions of surface cleanliness/activity and mass transport. For dilute solutions of ethanol in 1 N perchloric acid (HClO(4)), oxidative adsorption rates maximize at 0.3 V. drop off at more cathodic potentials due to competition with adsorbed hydrogen and drop off at more anodic potentials due to oxidative processes that produce products released to the electrolyte. The time and concentration dependence of adsorption follows relationships that are common for adsorption on a heterogeneous surface. Some evidence are presented supporting a mechanism for production of soluble products that does not involve the adsorbed species that are detected through the measurement of blockage of hydrogen adsorption sites. Published by Elsevier B.V.