In this investigation, ternary aqueous electrolytes of chloride, nitrate, and sulfate with the common magnesium cation have been studied using the hygrometric method at 298.15 K. The water activities of the ternary systems {yMgCl2 + (1 - y)MgSO4}(aq) and {yMg(NO3)2 + (1 - y)MgSO4}(aq) are measured at total molalities from 0.35 molakg-1 to saturation for different ionic strength fractions (y) of MgCl2 or Mg(NO3)2, respectively, with y ) 0.20, 0.50, and 0.80. The obtained data allow the deduction of osmotic coefficients of the solvent. From these measurements, mixing ionic parameters are determined and used to predict the solute activity coefficients in the mixture, using Pitzer s model. The parameters oMN and aMNX are evaluated for these systems. The thermodynamic properties of the ternary aqueous systems nitrate, chloride, or sulfate with magnesium, {Mg/Cl/NO3/SO4}(aq), are compared with the data obtained for the system [MgCl2 + Mg(NO3)2](aq) already published in a previous work.4 The comparison shows that the hydration is affected by the nature of the solute, MgSO4, MgCl2, or Mg- (NO3)2, in the mixed aqueous solutions. These effects might be influenced by ion pairing, with no contact in Mg(NO3)2(aq) and with ion association in MgSO4(aq).
Compounds
#
Formula
Name
1
Cl2Mg
magnesium chloride
2
MgO4S
magnesium sulfate
3
MgN2O6
magnesium nitrate
4
H2O
water
Datasets
The table above is generated from the ThermoML associated json file (link above).
POMD and RXND refer to PureOrMixture and Reaction Datasets. The compound numbers are included in properties, variables, and phases, if specificied;
the numbers refer to the table of compounds on the left.