Activity coefficients and standard Gibbs free energies of transfer of NaCl and KCl from water to aqueous solution of 2-butoxyethanol by EMF studies

1993 ◽  
Vol 71 (12) ◽  
pp. 2038-2042 ◽  
Author(s):  
Yvonne MacPherson ◽  
R. Palepu
Keyword(s):  
Activity Coefficients ◽  
Empirical Equation ◽  
Glass Electrode ◽  
Free Energies ◽  
Selective Electrode ◽  
Cell Potential ◽  
Emf Measurements ◽  
Free Energies Of Transfer ◽  
The Mean ◽  
Mean Activity Coefficients

From the emf measurements of the cell Na- or K-glass electrode|2-butoxyethanol, H2O, NaCl or KCl|Cl ion-selective electrode, the standard potentials were determined at 298 K for five different compositions of the solvent. From the emf data the mean activity coefficients of NaCl and KCl were calculated and fitted to an empirical equation. The standard Gibbs free energies of transfer of NaCl and KCl from water to mixtures of water and 2-butoxyethanol were calculated from the cell potential.

Gibbs energies of transfer of individual ions from water to acetone + water solvents

1989 ◽  
Vol 67 (8) ◽  
pp. 1268-1273 ◽  
Author(s):  
Mahmoud Mohamad Elsemongy ◽  
Ahmed Ahmed Abdel-Khalek
Keyword(s):  
Glass Electrode ◽  
Aqueous Mixtures ◽  
Free Energies ◽  
Emf Measurements ◽  
Gibbs Energies ◽  
Electrode Potentials ◽  
Gibbs Energies Of Transfer ◽  
Acetone Water ◽  
Alkali Metal Halides ◽  
Dipolar Aprotic Solvents

The standard absolute potentials of hydrogen, Ag–AgX (X = Cl, Br, and I) and M/M+ (M = Li, Na, K, Rb, and Cs) electrodes in nine different acetone + water solvents containing up to 80 wt. % acetone were determined from the emf data at 25 °C of the cells: glass electrode/HCl (m), solvent/AgCl–Ag and glass electrode (M)/MX (m), solvent/AgX–Ag. The standard Gibbs free energies of a transfer of halogen acids and alkali metal halides as well as their constituent individual ions from water to the respective solvents were computed. The observed increases in [Formula: see text] values of all ions with increasing acetone content of the solvent and their relative order in each solvent were interpreted and discussed. A comparison of the present results with those obtained earlier in the dimethyl sulphoxide (DMSO) + water solvents shows the different nature of the two dipolar aprotic solvents, acetone and DMSO, in their aqueous mixtures. Keywords: acetone + water solvents, electrode potentials, emf measurements, individual ions, transfer free energies.

Free energies of transfer of alkali halides from water to urea-water mixtures at 25�C from EMF measurements

1976 ◽  
Vol 5 (6) ◽  
pp. 431-444 ◽  
Author(s):  
Asim K. Das ◽  
Kiron K. Kundu
Keyword(s):  
Alkali Halides ◽  
Free Energies ◽  
Emf Measurements ◽  
Free Energies Of Transfer

Osmotic and activity coefficients of some simple borates in aqueous solution at 25°

1969 ◽  
Vol 47 (12) ◽  
pp. 2271-2273 ◽  
Author(s):  
R. F. Platford
Keyword(s):  
Boric Acid ◽  
Activity Coefficients ◽  
Solubility Limit ◽  
Sodium Tetraborate ◽  
Sodium Metaborate ◽  
Partial Association ◽  
The Mean ◽  
Vapor Pressure Measurements ◽  
Mean Activity Coefficients ◽  
Osmotic Behavior

Activity coefficients for sodium tetraborate, potassium tetraborate, sodium metaborate, sodium fluoroborate, and orthoboric acid were derived from isopiestic vapor pressure measurements. The osmotic behavior of sodium tetraborate, at concentrations up to its solubility limit, was the same as that of the more soluble potassium salt. The mean activity coefficients of both tetraborates were quite low: 0.355 at 0.1 m; the activity coefficients of sodium metaborate and fluoroborate were less than those of sodium chloride, indicating partial association in solution.The boric acid results were not very reliable because boric acid apparently volatilized during the measurements, but the results obtained indicated that it behaves like a non-electrolyte at all concentrations up to saturation, with an activity coefficient never less than 0.92.

APPLICATION OF ION-SELECTIVE ELECTRODES FOR DETERMINING THE MEAN ACTIVITY COEFFICIENTS OF ELECTROLYTES (EXEMPLIFIED BY THE NaCl + Na2SO4+ H2O SYSTEM)

1989 ◽  
pp. 595-609
Author(s):  
P.YA. TISHCHENKO ◽  
A.S. BYCHKOV ◽  
A. HRABÉCZY-PÁLL ◽  
K. TÓTH ◽  
E. PUNGOR
Keyword(s):  
Activity Coefficients ◽  
Ion Selective Electrodes ◽  
The Mean ◽  
Mean Activity Coefficients
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