Mixed potentials and double electrodes

The potential adopted by a metal in aqueous solution is not always governed by the equilibrium which might be expected for simple cases. Other 

The standard potential of hydrogen is considerably more positive than that of zinc, but at potentials more negative than E, the rate of hydrogen dis- 

Resultant current-potential plot (A-B) for a mixed electrode. At the corrosion potential equal currents flow in opposite directions. 

The actual potential adopted by the system for different currents will follow the resultant line AB which iXE = jE corr. gives equal currents flowing in opposite directions. The species co-reducing need not be hydrogen but may be any species reducing at a more positive potential than M .  

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