J. B. Macaskill

Osmotic coefficients of aqueous sodium carbonate solutions at 25°C

Isopiestic vapor pressure measurements are reported for aqueous sodium carbonate solutions at 25°C using sodium chloride as reference electrolyte. Osmotic and activity coefficients are calculated from the concentrations of the solutions in isopiestic equilibrium. The results are used to calculate the trace activity coefficients of carbonate ion in sodium chloride solutions; these should approximate the trace activity coefficient of carbonate ion in seawater. The solubility of sodium carbonate in water at 25°C has been determined.

Isopiestic measurements on aqueous mixtures of sodium chloride and strontium chloride

Isopiestic measurements have been made on NaCl−SrCl2 mixtures at 25°C over the ionic strength range 0.6–6 mole-kg−1. The results are interpreted in terms of current mixed-electrolyte treatments. The mixing behavior in this system is comparatively simple, but the Pitzer treatment is still clearly superior to the other treatments.

Osmotic and activity coefficients of monomethyl-dimethyl-, and trimethylammonium chlorides at 25°C

The osmotic and activity coefficients of monomethyl-, dimethyl-, and trimethylammonium chlorides in aqueous solution have been determined at 25°C by the gravimetric isopiestic method. The measurements extend from 0.1 molal (m) to 20, 17, and 15 mol-kg−1, respectively, for the three salts. In the region below 2m, the osmotic coefficients decrease in the order NH4Cl>MeH3NCl>Me2H2NCl>Me3HNCl>Me4NCl, and above 3m the order is reversed. The intermediate members of the series have identical osmotic coefficients at the crossover molality of 3.0. It is suggested that the behavior at low molalities reflects primarily ion-dipole interactions, decreasing as the cation size increases, whereas hydrophobic (structure-making) interactions, increasing in importance with the number of non-polar methyl substituents, are predominant in concentrated solutions of these salts.

Activity coefficient of hydrochloric acid in aqueous solutions of sodium chloride

AbstractElectromotive-force measurements of the cell

Standard potential of the silver-silver chloride electrode in 10, 20, and 40 wt.% ethanol/water solvents at 25, 0, −5, and −10°C

Pt;H_2 \left( {g,1{\text{ }}atm} \right)|HCl\left( {{\text{m}}_A } \right),NaCl\left( {{\text{m}}_B } \right)|AgCl;Ag

Activity and osmotic coefficients oft-butylammonium chloride; Activity coefficients of HCl in mixtures with tris hydrochloride ort-butylammonium chloride at 25°C

have been made at temperatures between 5 and 45°C at values ofmA+mB of 0.1, 0.3809, 0.6729, and 0.8720 mole-kg−1. The activity coefficients of HCl in HCl/NaCl mixtures and the Harned coefficients α12 have been obtained. The change of α12 with total molality is consistent with the existence of binary interactions between H+ and Na+ ions. The linear variation of the relative partial molal heat content with the fraction of NaCl in the mixture suggests that an analog of the Harned rule exists for this thermodynamic quantity.

Activity coefficients of hydrochloric acid and ionic interactions in the system HCl-LiCl-H2O from 5 to 45°C

The osmotic coefficients ϕ and activity coefficients γ± of aqueous solutions of HBr depend largely on emf measurements utilizing the silver-silver bromide electrode. There is evidence, however, that side reactions between AgBr and bromide ion render this electrode unreliable when the HBr molality (m) exceeds 2 mol-kg−1. It is shown, however, that the isopiestic vapor-pressure technique is capable of yielding data for HBr at higher molalities. New emf measurements of cells with hydrogen and AgBr/Ag electrodes at 25°C have been combined with literature data to recommend values for the activity coefficients of HBr in the dilute range. These have been supplemented by isopiestic measurements vs. NaCl and CaCl2 reference solutions in the range of HBr molalities from 0.7 to 6.2m. A table of ϕ and γ± at 25°C at round molalities from 0.005 to 6.0 is presented.

Specific interactions in mixed electrolyte solutions from solubility measurements

AbstractIn order to facilitate the measurement of thermodynamic quantities at temperatures below 0°C in ethanol/water solvents, the standard potential of the silver-silver chloride electrode in 10, 20, and 40 wt.% ethanol has been determined at 25, 0, −5, and −10°C. Electromotive force measurements of cells of the type