Fused salt cryoscopy

Cryoscopy. Souchay (40) has summarized the application of fused salt cryoscopy to ionic solutes. Obviously two limitations are inherent in this method. Under ordinary pressures, measurements are possible at only one temperature—namely that of the transition point (e.g., ca. 32.38°C. in the case of Na2S04 10 H20). Secondly, the solute is being examined in solutions of high ionic strength only. Isopiestic vapor pressure measurements have been used as a variation, which, in principle, eliminate both limitations. However, it does not appear that it is as yet possible to analyze such data to yield equilibrium constants (33). Furthermore, Tobias has cast doubt upon the inherent accuracy of the method when the polyions contain more than 3 or 4 metal ions (41). 

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