A General Method of Calculating the Water Activity of Supersaturated Aqueous Solutions from Ternary Data

Abstract

Recently developed methods of predicting water activities of multicomponent aqueous solutions use binary data. At high concentrations these methods are limited inasmuch as they require binary data beyond the solubility limit of individual solutes. A method is proposed whereby ternary water activity data may be used to calculate water activities of supersaturated binary solutions. The new method is compared with two extrapolation procedures on a known system and gives the best agreement. Values of the water activities for supersaturated solutions of KNO 3 (3.8 to 7.6 m) and K 2 SO 4 (0.7 to 2.3 m) at 25 °C are obtained.