Re-evaluation of the Thermodynamic Activity Quantities in Pure Aqueous Solutions of Chlorate, Perchlorate, and Bromate Salts of Lithium, Sodium or Potassium Ions at 298.15 K

The Hückel equation used to correlate the experimental activities of dilute alkali metal chlorate, perchlorate or bromate solutions up to a molality of about 1.5 mol⋅kg⁻¹ contains two electrolyte-dependent parameters: B {that is related closely to the ion-size parameter (a ^∗) in the Debye–Hückel equation} and b ₁ (this parameter is the coefficient of the linear term with respect to the molality, which is related to hydration numbers of the ions of the electrolyte). In more concentrated solutions up to 7 mol⋅kg⁻¹, an extended Hückel equation was used, it contains additionally a quadratic term with respect to the molality, and the coefficient of this term is the parameter b ₂. Parameters for the Hückel equations were evaluated from isopiestic data for LiClO₃, LiBrO₃, LiClO₄, NaClO₃, NaBrO₃, NaClO₄, KClO₃, and KBrO₃. In these estimations, the Hückel parameters determined recently for NaCl solutions were used. The resulting parameter values were tested with the vapor pressure and isopiestic data available in the literature for solutions of these salts. Most of these data were reproduced within experimental error by means of the Hückel or extended Hückel equations, at least up to a molality of 3.0 mol⋅kg⁻¹, for all salts considered. Reliable activity and osmotic coefficients for solutions of these salts can, therefore, be calculated by using the new Hückel equations, and they are tabulated here at rounded molalities. The activity and osmotic coefficients obtained from these equations were compared to the values reported in several previous tabulations.