Isopiestic determination of the osmotic and activity coefficients ofZnSO4(aq) atT= 298.15 K, and the standard potential of the electrochemical cell ZnHgx(two phase)| ZnSO4(aq)| PbSO4(s)| PbHgx(two phase)

Some highs and lows (and in-betweens) of solubility measurements of solid electrolytes

“…A recent independent study by Pinho and Macedo [ 12], employing a similar approach to the present work but drying at 120 °C, reported a solubility of 26.483 ± 0.013 g NaCI/100 g sin. After correction for -0.15 mass % residual water [9,10] in the dried NaCI(s), this result corresponds to 26.44 ± 0.02 g NaCI/100 g sin. The agreement between these recent studies offers hope that the solubilities of simple salts in amenable solvents can, with due care, be determined routinely with a relative accuracy of better than ±0.1 %, at least at 25 oc.…”

“…Known masses of solution were evaporated to dryness in glass beakers at sub-boiling temperatures (usually -80 oq and then dried to constant mass at 150 oc in a laboratory oven at atmospheric pressure. The average solubility obtained at 25 °C from over 50 measurements, after correction assuming 0.15 mass % of residual water in the dried samples [9,10], was 26.45 ± 0.02 g NaCI/100 g sin. This value agrees exactly with the IUPACrecommended value [4] of 26.450 ± 0.073 g NaCI/100 g sin discussed above.…”

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

“…Miladinović et al [26,27] subsequently reported isopiestic measurements using high-purity ZnSO 4 that yielded osmotic coefficients in essential agreement with those of Albright et al [21], and the combined results from these three isopiestic studies yield an accurate characterization of the osmotic coefficients from 0.1 mol·kg -1 to supersaturated molalities.…”

“…Rard and Clegg [20] Albright et al [21] reported extensive isopiestic measurements for ZnSO 4 (aq) at 298.15 K using well characterized ZnSO 4 with a mole-fraction purity of 0.9993. Their measurements extend to supersaturated molalities and included solubilities.…”

“…Albright et al [21] reported that the equation of Pitzer and Mayorga [48] (the parameter transformation equations of Rard and Wijesinghe [66] are based on the osmotic coefficient).…”