The Water-activity of Supersaturated Aqueous Solutions of NaCl, KCl, and K2SO4 at 25°C

Reverse application of the Reilly–Wood-Robinson and Zdanovskii–Stokes–Robinson equations to the water-activity data of various ternary aqueous systems containing NaCl, KCl, K2SO4 as one of the components yields self-consistent estimates of the water-activity of binary aqueous supersaturated solutions of the individual salts; these can be further extended by curvilinear extrapolation to give: [Formula: see text] with A1 = −3.28806 × 10−2, A2 = 1.12512 × 10−4, A3 = −4.30034 × 10−4, A4 = 2.70506 × 10−5, A5 = 1.43435 × 10−6, A6 = 1.30209 ×10−7, A7 = −1.51941 × 10−8, A8 = 1.00520 × 10−9, A9 = −4.21593 × 10−10, A10 = 2.62532 × 10−11, valid to aw(NaCl) = 0.5422, [Formula: see text][Formula: see text]with B1 = −3.21884 × 10−2, B2 = 9.77773 × 10−4, B3 = −6.05349 × 10−4, B4 = 1.18422 × 10−4, B5 = −7.91572 × 10−6, B6 = −3.88125 × 10−8, B7 = 1.55125 × 10−8, valid to aw(KCl) = 0.7115, [Formula: see text][Formula: see text] with C1 = −4.16810 × 10−2, C2 = 1.16033 × 10−2, C3 = −4.80543 × 10−3, C4 = 7.15536 x 10−4, valid to [Formula: see text][Formula: see text]