Two Problems in Electrochemistry

During the nineteenth centnry, opinions were divided as to where in galvanic cells of the type 

It will be assumed that the interactions between each of metals (1) and (2) and the corresponding surface layers of the electrolyte solution are approximately identical, and also that specific adsorption of ions does not occur in the system being considered. In this case the values of the expressions in the last two sets of brackets in Eq. (9.10) become zero, and from (9.10) and (9.11) an important relation is obtained which links the OCV of galvanic cells with the Volta potential  

This expression explains the qualitative agreement found to exist between the OCV values of galvanic cells and the Volta potentials of the corresponding metal pairs. But through terms and it also explains why OCV values depend on solution composition. All parameters of this equation can be measured experimentally. 

Equation (9.12) yields another important result When both electrodes are at the potential of their respective PZC (and the values of are zero), the cell voltage (which is the PZC potential difference between the two electrodes) will be equal to the Volta potential between the corresponding metals  

In a number of cases, Eqs. (9.12) and (9.13) are in good agreement with experimental data. However, sometimes the quantitative agreement is not as good, and this can be attributed to the approximations made in connection with Eq. (9.12). Therefore, when comparing the calculations with experiment, one can reach certain conclusions as to the way in which the surface potentials vary (i.e., as to the way a metal interacts with the electrolyte). 

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