Isopiestic determination of the osmotic and activity coefficients of {(1 − y)H2SO4 + yNa2SO4}(aq) at the temperature 298.15 K II. Results for y = (0.12471, 0.24962, and 0.37439)

Isopiestic determination of the osmotic and activity coefficients of {zH2SO4+(1−z) MgSO4}(aq) at the temperatureT=298.15 K. I. Results forz=(0.85811, 0.71539, and 0.57353)

“…All apparent masses were converted to masses. Assumed molar masses were 98.074 g·mol −1 for H 2 SO 4 , 58.443 g·mol −1 for NaCl, and 120.364 g·mol −1 for MgSO 4 .…”

“…In most cases the experimental thermodynamic results are limited to a small portion of the available composition region. The most thoroughly studied of these systems is {zH 2 SO 4 + (1 − z)Na 2 SO 4 }(aq) for which isopiestic results are available up to supersaturated molalities for 1 e z e 0 at the temperature T = 298.15 K, (3)(4)(5) and for 0.5 e z e 0 at elevated temperatures. (6,7) The thermodynamic activities for {zH 2 SO 4 + (1 − z)Na 2 SO 4 }(aq) have been analyzed by Pitzer's equations.…”

“…(9,10) Thus, the only equilibrium that need be considered in the mixtures is that for formation of HSO − 4 (aq). However, the association constants are much larger for solutions of divalent metal sulfates MSO 4 (aq), (11,12) and thus it might be necessary to include specifically the presence of equilibrium amounts of the neutral divalent-metal sulfate complexes along with the HSO − 4 (aq) ion in order to obtain quantitative models for the thermodynamic properties of {zH 2 SO 4 + (1 − z)MSO 4 }(aq).…”

Osmotic and Activity Coefficients of the {xZnCl2+(1−x)ZnSO4}(aq) System at 298.15 K

“…Rard [69] used a simplified speciation calculation and found that a plot of φ e versus I e for {xH 2 SO 4 + (1 -x)Na 2 SO 4 }(aq) showed more regular behavior as a function of x with no crossovers. Values of φ e for {xZnCl 2 + (1 -x)ZnSO 4 }(aq) are reported in Table 3 and are plotted in Fig.…”

“…These terms were not included in the model equations because they are nearly insignificant at the ionic strengths of our isopiestic measurements. some of the mixture φ curves fall below the φ curve of Na 2 SO 4 (aq) [69]. Sulfuric acid, like zinc chloride, is a partially associated electrolyte, and the complicated composition dependence of φ observed for these three mixed-electrolyte systems are obviously largely the result of changes in speciation due to complex formation.…”