Concentration Cell
A galvanic cell in which both electrodes are identical and the potential arises solely from a difference in concentration.
Formula / equation
E = (0.0592/n) log(C₂/C₁)
Unit
V
In depth
Because the standard potentials cancel, the entire emf comes from the Nernst concentration term, and the cell runs until both concentrations are equal. Small though the voltages are, concentration cells make extremely sensitive analytical devices and explain some forms of localised corrosion.
Examples in the real world
Two copper electrodes in 0.1 M and 0.001 M CuSO₄ giving about 0.059 V.