Presentation of a Model Describing the Osmotic Coefficients and the Activities of Water for Electrolyte Solutions

This work presents a model for thermodynamic properties of the uni-univalent electrolytic solutions
based on a linear relation between a dimensionless-thermodynamic potential constructed for solvent
and a newly defined probability-distribution function of water molecules around the hydrated central
ion. The model allows quantitative reproduction of the osmotic coefficients for the uni-univalent
electrolytic solutions, especially some hydroxides of alkali metals and monoacids such as NaOH,
KOH, LiOH, HF, HCl, HBr, HI, HNO3 and H(HSO4), within experimental accuracy. A comparison is
made of the results of the presented model with the Pitzer's equation. This paper also introduces an
alternative approach for the probability-distribution function, which makes the model be able to extend
to the single electrolyte solutions with various valent types.