Among the properties of solutions such as boiling point elevation is a little-known colligative property described in 1890 by Walther Nernst and called "reduction of solubility". In common with the other colligative properties, it can be used for determining molecular masses. This method involves a binary liquid-liquid system of an organic solvent and water. After equilibrium, the concentration of the organic solvent in the aqueous phase is determined. Then a measured mass of a substance of unknown molecular mass is dissolved in the organic phase of the liquid-liquid system. The reduction of the solubility of the organic phase in the aqueous phase is a function of the molar concentration of the unknown in the organic phase. We tested this experiment to examine its potential pedagogic use. Although quite accurate results can be obtained, we found the method to be extremely limited.
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Citation
Beall, Herbert; Riccardino, Patrick A. J. Chem. Educ.2001 78 511.
Keywords
History / Philosophy; Liquids; Physical Chemistry; Solutions / Solvents
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