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Analysis of several methods to determine the activity of water in solutions of strong electrolytes
Author(s) -
Correa H. A.,
Vega R. E.
Publication year - 1989
Publication title -
the canadian journal of chemical engineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.404
H-Index - 67
eISSN - 1939-019X
pISSN - 0008-4034
DOI - 10.1002/cjce.5450670516
Subject(s) - ternary operation , supersaturation , thermodynamics , electrolyte , binary number , activity coefficient , chemistry , strong electrolyte , ternary numeral system , mathematics , physics , computer science , aqueous solution , arithmetic , electrode , programming language
Abstract The methods of Zdanovskii‐Stokes‐Robinson ( ZSR ), Reilly‐Wood‐Robinson ( RWR ), Pitzer and Correa, to determine water activity in ternary solutions of electrolytes from data for water activity in binary solutions, were analysed. In addition, the first two methods were used to estimate the activity of water in supersaturated binary solutions using data from ternary solutions. Also, the equation of Correa for binary solutions was extrapolated to calculate the activity of water at supersaturation. The methods were tested using the experimental data (at 25°C) for nine ternary systems, with a common ion, involving the following ions: Li + , Na + , K + , Ca ++ , Mg ++ , Cl − and NO 3 − . Zdanovskii's method gave the best estimations of water activity in ternary systems. The method of Correa gave smaller standard deviations than the methods of Pitzer and RWR with the advantage that its application is simpler. For binary solutions at supersaturation, Correa's method gave better results than the method of ZSR and this, in turn, yielded smaller deviations than the RWR method.