The Physical Chemistry of Electrolytic Solutions.

A large number of quantitative studies have been made of the Gibbs energy of transfer (the solvent medium effect) for cations transferring from water into mixed aqueous−organic solvent systems, mainly at 25 °C. Nevertheless, no systematic effort appears to have been made to compile and analyze these data, particularly for multivalent cations. A critical review of this information and its presentation in a manner that permits comparison of different cations in a given solvent mixture and of a given cation transferring into different mixtures is therefore of value.

Gibbs energies of transfer of anions from water to mixed aqueous organic solvents.

A wide-ranging critically evaluated compilation of the standard molar enthalpies and entropies of transfer of electrolytes from water to mixed aqueous-organic solvents were shown. For this compilation, the reported values were recalculated to obtain a consistent format that enabled comparisons to be made among the data. These whole-salt data were then split into the transfer functions of the individual ions, using an appropriate extrathermodynamic assumption.

Enthalpies and Entropies of Transfer of Electrolytes and Ions from Water to Mixed Aqueous Organic Solvents

The structures of trans-[CoIII(cyclam)(NCS)2](NCS) and of [CoII(Me4cyclam)(NCS)]2[Co(NCS)4]·MeOH have been established by X-ray diffraction methods. The solvatochromic behavior of the trans-[Co(cyclam)(NCS)2]+ cation in several binary aqueous solvent mixtures is reported. Transfer chemical potentials for this complex from H2O into MeOH-H2O mixtures have been established from solubility measurements on its thiocyanate salt. The solvatochromic behavior of this cation is discussed in the context of other solvatochromic inorganic complexes; its transfer chemical potentials are discussed in relation to those of other cobalt(III) complexes.

Structure, solvatochromism, and solvation of trans-[Co-III(cyclam)(NCS)(2)](NCS) and the structure of [Co-II(Me(4)cyclam)(NCS)](2)[Co(NCS)(4)]MeOH

Thermodynamics of the silver—silver thiocyanate electrode in water—dioxane mixtures at different temperatures

Thermodynamics of hydrochloric acid in dioxane—water mixtures

Electromotive force measurements of the cell Pt, H2/HBr(m), dioxan(X) H2O(Y)/AgBr/Ag have been made at 15, 25, 35 and 45°C for solvent compositions X= 10, 20, 30, 40, 60 %(w/w) of dioxan. These have been used to evaluate the standard potentials of the cell, the mean activity coefficient of HBr (molal scale) and the thermodynamic functions (mole-fraction scale) for the transfer of HBr from water to the respective dioxan + water media. The ΔG°t(free energy of transfer of the acid from water to various solvents) values along with those for hydrochloric acid, are briefly discussed in relation to ion solvation.

Thermodynamics of hydrobromic acid in dioxan + water mixtures from electromotive force measurements at different temperatures

Thermodynamic studies of hydrogen iodide in dioxane-water mixtures from electromotive force measurements

The free enrgies of transfer (ΔG t 0 ) of H+, Cl−, Br−, I− and SCN− ions from water to 10, 20, 30 and 40% dioxanewater mixtures have been studied from potentiometric measurements. For anions the ΔG t 0 values are in the order Cl−>Br−>SCN−>I−.

Prasanna K. Das

Papers

Thermodynamics of hydrochloric acid in dioxane—water mixtures

Thermodynamics of hydrobromic acid in dioxan + water mixtures from electromotive force measurements at different temperatures

Thermodynamic studies of hydrogen iodide in dioxane-water mixtures from electromotive force measurements

Studies on hydrogen, halides and thiocyanate ions in dioxane-water mixtures at various temperatures

Thermodynamics of the transfer of (H+ SCN−) from water to methanol + water mixtures from the study of silver—silver thiocyanate electrodes