Chemical equilibria thermodynamics reference electrodes

As with any chemical process, it is logical first to consider the thermodynamics. Suppose the potential of the working electrode vs. the reference electrode is monitored while no current is allowed to flow. Under these circumstances no chemical change can occur at the surface and the solution composition will remain unchanged and uniform. The working electrode will take up its equilibrium (or reversible) potential E, which may also be calculated from the Nernst equation ... 

Reference electrodes. The thermodynamic equilibrium of any other chemical or electrochemical reaction can be calculated in the same manner, provided the basic information is found. Table D.8 contains the chemical description of most reference electrodes used in laboratories and field units, and Tables D.9 and D.IO, respectively, contain the thermodynamic data associated with the solid and soluble chemical species making these electrodes. Table D.ll presents the results of the calculations performed to obtain the potential of each electrode at 60°C (i.e., away from the 25°C standard temperature). 

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