Open AccessA simple method to derive the water activities of highly supersaturated binary electrolyte solutions from ternary solution data
Author(s) -
Chan Chak K.,
Ha Zhanyao
Publication year - 1999
Publication title -
journal of geophysical research: atmospheres
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.67
H-Index - 298
eISSN - 2156-2202
pISSN - 0148-0227
DOI - 10.1029/1999jd900942
Subject(s) - ternary operation , ionic strength , supersaturation , thermodynamics , aqueous solution , electrolyte , activity coefficient , chemistry , ionic bonding , ternary numeral system , mixing (physics) , inorganic chemistry , ion , physics , organic chemistry , electrode , quantum mechanics , computer science , programming language
Using mixing rules in electrolyte models for estimating the thermodynamic properties of multicomponent mixtures requires knowledge of data for each binary solution. Very often, a ternary solution in a single‐particle levitation experiment can achieve a higher ionic strength as compared with the ionic strengths derived from any of the binary solutions alone. Using water activity data of ternary solutions and the Zdanovskii‐Stokes‐Robinson and the Kusik and Meissner (KM) equations, water activities of binary solutions of (NH 4 ) 2 SO 4 , NaCl, and NH 4 Cl at supersaturations higher than any previously reported are calculated. With available data from the literature on aqueous supersaturated droplets of NH 4 NO 3 ‐(NH 4 ) 2 SO 4 ternary solutions and letovicite at ambient temperatures, water activities (>0.32) of (NH 4 ) 2 SO 4 solutions for ionic strengths up to 112 mol kg −1 are obtained. The new water activity relation enables the use of the KM and Pitzer models at higher ionic strengths than in previous research. Applying the same method to the data on (NH 4 ) 2 SO 4 ‐NaCl and NH 4 NO 3 ‐NaCl systems yields water activities (>0.28) of NaCl solutions for ionic strengths up to 25 mol kg −1 . Similarly, water activities (>0.34) of NH 4 Cl solutions up to 42 mol kg −1 are calculated from the measured data on NH 4 Cl‐NH 4 NO 3 and NH 4 Cl‐(NH 4 ) 2 SO 4 systems. New water activity measurements for the NH 4 Cl‐NH 4 NO 3 , NH 4 Cl‐(NH 4 ) 2 SO 4 , and NH 4 NO 3 ‐NaCl systems are also reported.