J. H. Reedy — Anodic Potentials of Silver. 293 



reaction potentials of silver with the halogen and hydroxyl 

 ions. The potentials are plotted as ordinates and the logarithms 

 of the dilutions of the ions as abscissae. For dilutions up to 

 1000 liters the ionic concentration of the anions was calculated 

 from conductivity data ; for dilutions of over 1000 liters the 

 ionization is assumed to be complete. These potentials were 



Fig. 5. 



.800 



-.200 



IOOO 



IOOOO IOOOOO 



Logarithms of Dilutions 



Fig. 5. Effect of concentration on reaction potentials on silver anodes. 



obtained on silver anodes coated electrolytically with the silver 

 compound corresponding to the anion of the solution. 



The lines for bromine and iodine ions are apparently 

 straight ; that is, the potential is a logarithmic function of the 

 dilution, although the slope is greater than would be expected 

 from the JN'ernst formula. Instead of -0585 (for 22°, the 

 average temperature of the experiments), the slope appears to 

 be *0616 — about 10 per cent higher than the theoretical value. 

 No explanation of this deviation is offered. At ordinary 

 concentrations (1 to "001 molar) the lines for chlorine and 

 hydroxyl ions are straight, just as in the case of bromine and 

 iodine ions. But at higher dilutions the increase of potential 



