The Heats of Solution and Related Thermodynamic Properties of Sodium Chlorate in Water and Water–Dioxane Mixtures

Abstract

The heats of solution of sodium chlorate in water, and in several water-dioxane mixtures, have been determined experimentally at concentrations of salt ranging from 0.01 molal to saturation. For the dilute region, a direct method was used but for the concentrated range the method was that of diluting the saturated solution. The free energy decreases due to dilution have been calculated from previously determined activity coefficients. Using these data, the entropy changes have been evaluated.The graph of heat of solution vs. concentration of sodium chlorate passes through a minimum for the solutions more concentrated in dioxane, but not for water and weak dioxane mixtures. A tentative explanation of this is offered.