A method to apply Zavitsas' aqueous electrolyte model to multicomponent solutions and its equivalence to Zdanovskii's rule

Abstract

Zavitsas developed an aqueous electrolyte thermodynamic model and applied it to single electrolyte solutions previously. Here, a method to apply the model to multicomponent solutions is derived by setting the water activity to the mole fraction of free water in the mixture. The method is shown to work effectively for the CsBr-KNO 3 -H 2 O and CsCl-KNO 3 -H 2 O systems at 100.3 C even at concentrations greater than 6 molal. The largest error in the prediction of water activities was just À0.00365 for the CsBr-KNO 3 -H 2 O system and À0.00631 for the CsCl-KNO 3 -H 2 O system.Zavitsas' model naturally obeys Zdanovskii's rule because when two electrolyte solutions with the same fraction of free water are mixed together, water is obviously going to have that same fraction in the mixture. This means that Zavitsas' model will likely work well for the many electrolytes that obey Zdanovskii's rule.

Modeling Henry's law and phase separations of water–NaCl–organic mixtures with solvation and ion-pairing

“…To bridge existing knowledge gaps, Zivitsas, 6,7,20,21 Heyrovská, 22–26 Reynolds, 8,27–29 Wexler 30–34 and Wilson 5,9,35,36 have recently explored mechanistic mass action models that incorporate solvation and ion-pairing phenomena. Each of these models is distinct, with some approaches retaining electrostatic terms.…”

Tracking nitrite's deviation from Stokes–Einstein predictions with pulsed field gradient 15N NMR spectroscopy

“…Recent research has sought to address those ambiguities through the application of hydration models to correlate the activity of water with the solubility of NaNO 2 in single- and multi-component aqueous solutions. 10,11 The solubility of concentrated NaNO 2 in aqueous solutions of NaOH has also been measured and the solutions were characterized to assess the extent of OH − mediated ion-pair formation. 12 A subsequent study correlated the vibrational properties of NO 2 − to the rheological and thermodynamic properties of the solution.…”