Dissolution of Copper in Sulfuric Acid Solutions

When copper disks rotate in sulfuric acid solutions, the observed rate of dissolution is first order with respect to the concentration of dichromate ion used as a depolarizer. By studying the effect of temperature and stirring speed at high and low acid concentrations, the process is shown to be determined completely by the rate of transport of dichromate ion to the reacting surface. This has been confirmed by studying the effect of different surface preparations, by measuring the rate of reaction of brass and amalgamated copper with these solutions, and by comparing the observed values with the theoretical rates. The effect of blocking off progressively larger areas of the working surface is reported.