Thermodynamic Properties of Aqueous Mixtures LiCl + KCl + NH4C1 + H2O. Water Activity and Osmotic and Activity Coefficients at 298.15 K

摘要

The thermodynamic properties of the quaternary aqueous system LiCl + KCl + NH4C1 + H2O have been studied using the hygrometric method by measuring the diameter of droplets of the reference solution of NaCl(aq) as a function of the surrounding relative humidity of the studied system. The water activities of aqueous electrolyte mixtures of LiCl + KCl + NH4Cl + H2O were experimentally determined at T = 298.15 K at a total ionic strength from 0.6 mol·kg~(-1) to 4.8 mol·kg~(-1) for different ionic strength fractions y of one of the three solutes (y=I_(XCl)/I_(tot)), ranging from 1/3, 1/2, to 2/3 with the constant ratio r of molality of the two other solutes of unity (r = m_(YCl)/m_(ZCl)). The data allow the deduction of osmotic coefficients. The results obtained were correlated using Pitzer's model, Dinane—Pitzer's model, the Robinson—Stokes (RS) equation, the Lietzke—Stoughton (LS II) model, and Dinane's mixing rules ECAI and ECAII. The solute activity coefficients of the components in the mixture were also determined for different ionic strength fractions y of solutes.