The enthalpy of dilution of some 1-1 and 2-1 electrolytes in aqueous solution

Wing H. Leung, Frank J. Millero

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27 Scopus citations


The enthalpies of dilution of aqueous solutions of RbCl, CsCl, NaF, NaBr, NaI, CaCl2, SrCl2, BaCl2, NaHCO3, and Na2CO3 in the molality range 0.1 to 1.0 mol kg-1 have been determined at 303.15 K with a microcalorimeter. The relative apparent molar enthalpies Lφ of these solutions have been determined with the aid of an extended form of the Debye-Hückel limiting law: Lφ = SHI 1 2[{1 + (I/mθ) 1 2}-1 - σ/3] + BI + CI 3 2, where SH is the limiting-law slope, σ = "; 3 ( I m) 3 2';[";1 + ( I m) 1 2'; - ";1 + ( I m) 1 2';-1 - 2 ln";1 + ( I m) 1 2';], B and C are empirical constants, I is ionic strength, and m is a standard molality (1 mol kg-1). This equation fits the experimental results with a standard deviation of ±2 calth mol-1 for all the salts. The parameters B and C were examined by relating them to properties of the ions that make up the various electrolytes; B was found to be linearly related to the reciprocal of the crystallographic radius and C was found to be directly related to B.

Original languageEnglish (US)
Pages (from-to)1067-1078
Number of pages12
JournalThe Journal of Chemical Thermodynamics
Issue number11
StatePublished - Nov 1975

ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics
  • Materials Science(all)
  • Physical and Theoretical Chemistry


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