Electrochemical measurements of partial molar functions

The equilibrium potential of this cell is the difference between the potential of the metal in the alloy state minus the potential of the pure metal 

It is related to the partial molar Gibbs energy of the component A by the equation 

The sign is defined by the procedure of Section 3.1.2, Eqs. (3.14) and (3.15). The alloy electrode (electrode I) is measured versus the pure metal electrode (electrode II) and a cathodic current is assumed through the alloy electrode determining the direction of the cell reaction. 

To measure the equiUbrium potential of such a cell several experimental restrictions must be observed. Some examples are given in the following listing  

For these reasons, potential measurements of alloys are frequently made at higher temperatures with solid electrolytes or by using molten salt electrolytes. Measurements in aqueous electrolytes and at room temperatures were mostly restricted to mercury alloy (amalgam) electrodes. 

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