268 PROPERTIES OF ELECTRICALLY CONDUCTING SYSTEMS 



cases, the solubility may even be increased. The solubility of certain 

 salts, such as silver chloride, 31 * is greatly increased on addition of an 

 electrolyte with a common ion. Since it has been shown that this effect 

 is chiefly due to the formation of complex ions, a discussion of these 

 systems may be omitted. 



The solubility of binary salts is materially increased on the addition 

 of a salt without a common ion. This may be accounted for on the 

 assumption that metathetic reaction takes place between the ions of the 

 saturating salt and the solvent electrolyte, the increased solubility being 

 due to the formation of the corresponding un-ionized molecules. If the 

 isohydric principle is assumed to hold for such mixtures, the resulting 

 values obtained for the ion product and the concentration of the un- 

 ionized salt are found to vary with the concentration of the added elec- 

 trolyte in a manner similar to that found in mixtures with a common ion. 

 Here again it is not possible to reach a conclusion relative to the nature 

 of the processes involved with any considerable degree of certainty. 



c. The Solubility of Salts of Higher Type in the Presence of Other 

 Electrolytes. The solubility relations in the case of salts of higher type 



TABLE CVI. 



SOLUBILITY OF SILVER SULPHATE IN WATER AT 25 IN THE PRESENCE OF 



OTHER ELECTROLYTES. 



Concentration of 



Salt Salt Solubility 



None .... 0.00 53.52 



KN0 3 24.914 57.70 



49.774 61.13 



99.87 67.93 



Mg(N0 3 ) 2 24.764 59.44 



49.595 64.32 



99.46 72.70 



AgN0 3 24.961 39.09 



49.86 28.45 



99.61 16.96 



K 2 S0 4 25.024 50.66 



50.044 49.35 



100.00 48.04 



200.03 48.30 

 MgS0 4 20.022 52.21 



50.069 50.93 



100.04 49.95 



200.05 49.60 



'"Forbes, J. Am. Chem. Soc. 33, 1937 (1911). 





