26 



ELECTROCHEMICAL INVESTIGATION OF LIQUID AMALGAMS 



Comparison of the observed and calculated potentials of the indium 

 amalgam cells shows the behavior of these cells to be similar to those of 

 thallium, but in a less degree. The cells with concentrated amalgams show 

 considerable deviation from the theoretical value, not so much, however, 

 as with thallium amalgams of the same concentration. On the other hand, 

 at great dilutions the agreement between the observed and calculated 

 values is exceedingly close. The cell Gi-G2 differs by only 0.000019 volt 

 or 0.3 per cent from the theoretical potential. 



The significance of the results of these measurements can best be illus- 

 trated by the same sort of curve as was employed in the case of thallium 

 amalgams. The curve for indium amalgams is shown in fig. 7. As before, 

 the common logarithms of the concentration ratios are plotted as abscissae 

 and the value of the deviations from the simple concentration law as 

 ordinates. The sign of curvature is the same as with thallium, since both 

 deviate in the same direction from theory. 



The significance of this curve also will be discussed later. 



H 



log a | g4 logS log 16 log 33 Iog64 log!23 log 256 

 Fig. 7. The Deviations of the Electromotive Force of Indium Amalgams. 



J? T c 



Deviations from the expression ir = *~ In -\ are plotted in millivolts as ordinates, 



3^ c i 



the logarithms of the concentration ratios as abscissae. The most concen- 

 trated amalgam contained 1.92 per cent by weight of indium and 98.08 

 per cent by weight of mercury. A horizontal line on the diagram would 

 indicate complete fulfilment of the concentration law. This curve is almost 

 if not qxiite independent of temperature, at least between o* and 30. 



