Experimental Studies of Electrochemical Cells

The experimental study of electrochemical cells contributed in an important way to the acquisition of thermodynamic data for electrolyte solutions. Experimental methods for precisely measuring the EMF of these systems were well established in the first half of the twentieth century [3]. As a result, many data were obtained for electrolyte activities and for important solution equilibria. Some examples of the experiments involved in these studies are given in this section. 

When an electrochemical cell is set up without liquid junctions it can be used to study the thermodynamic properties of the electrolyte involved. This requires that one electrode be reversible to the cation of the electrolyte and the other to the anion. A simple example is the cell 

Molality of HCL 10 X EMF EjW Activity Coefficient Y Molality of HCl 10 X ttig EMF EfV Activity Coefficient Y  

The experimental results for cell (9.5.1) can be used to determine the mean activity coefficient of the electrolyte HCl. Expressing the individual ionic activities in terms of the mean activity coefficient and the electrolyte molality, equation (9.5.3) can be rewritten as 

In order to extract the activity coefficient at each concentration one must first determine the standard EMF Taking the term In me, which is known, to the left-hand side, one may write 

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