2.The removal of O at the electrode surface by its conversion to R sets up a concentration gradient across the stagnant solution layer. The species O diffuses from the stirred region across this layer to the electrode surface where it is electrolyzed to R, which then diffuses back across the stagnant layer to the bulk solution. Thus, the electrolysis process is controlled by a combination of (a) mass transfer of O to across the across the stagnant layer by the laminar flow and (b) subsequent diffusion of O across the stagnant layer under the influence of the concentration gradient caused by electrolysis of O to R at the electrode surface to satisfy the Nernst equation.