Additivity of molar metachors of chlorides in aqueous solutions

Abstract

For the molar metachor, a quantity expressing the electrostatic contribution from free (nonassociated and noncomplexed) ions to the surface tension of aqueous solutions of electrolytes, its additivity was verified for completely dissociating chlorides of univalent and divalent metals at concentrations up to 5 mol dm-3. Owing to this property, the degree of dissociation could be estimated for associating components of solutions containing also completely dissociated electrolytes. Measurements revealed that NaCl, LiCl, MgCl2 and CaCl2 in mixed solutions are completely dissociated whereas ZnCl2, CdCl2 and UO2Cl2 at molar ratios NaCl:MeCl = 2:1 and higher ( at cCl- = 5 mol dm-3) are completely transformed into electroneutral and anionic chloro complexes, the latter forming ion pairs and triplets with Na+ ions.