Copper Deposition on an RDE

Copper is deposited on a RDE from a solution of CuSOa at concentration c, to which H2SO4 has been added, concentration s. Steady state, transport limited current at an RDE is assumed. There are three species in solution, and we denote their concentrations s a, b,c, respectively standing for [Cu +], [H+], and [804 ]. Their concentrations are initially c, 2s and c + s, respectively. The potential is cp. The three species will be indexed by = 1,2,3, or denoted by A, B, C, respectively. These are normalised as follows  

The governing equation for a transport limited electrolysis of a species j at the RDE is 

V being the kinematic viscosity in m s and a the rotation rate in units of s. The characteristic length, the diffusion layer thickness, is given as 

Note that they are related to the mobilities u sometimes more easily found, by D= 

The maximum (dimensionless) distance from the electrode to be considered is set at 

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