scholarly journals The Detemination of the Formation Constants of the Triiodide Ion in Water–Alcohol Mixed Solvents at Various Temperatures

1977 ◽  
Vol 50 (3) ◽  
pp. 566-569 ◽  
Author(s):  
Katumitu Hayakawa ◽  
Sumio Nakamura
Keyword(s):  
Mixed Solvents ◽  
Formation Constants ◽  
Water Alcohol

scholarly journals The behaviour of electrolytes in mixed solvents. Part I.—The free energies and heat contents of hydrogen chloride in water—Ethyl alcohol solutions

1929 ◽  
Vol 125 (799) ◽  
pp. 694-712 ◽  
Keyword(s):  
Hydrogen Chloride ◽  
Electric Fields ◽  
Mixed Solvents ◽  
Dielectric Constants ◽  
Free Energies ◽  
Dissolved Ions ◽  
Uniform Medium ◽  
The Mean ◽  
Solvent Molecules ◽  
Water Alcohol

Previous studies on the effect of a change of medium on tire properties of dissolved electrolytes have aimed at correlating the behaviour of the electrolyte with the mean physical properties, e. g ., dielectric constants, of the medium. While this approach may be justified in the case of solvents containing molecules of only one kind, it is not sufficient to regard a mixed solvent as a uniform medium affecting the dissolved ions solely through the effect of its dielectric constant on the electric forces between them. For the electric fields of ions exert a differential attraction on molecules possessing different degrees of polarisability and since tire more polarisable molecules must tend to congregate round the ions, the properties of the latter cannot depend solely on tire mean properties of tire medium. Studies on the behaviour of ions in such cases will throw light on the interaction between ions and solvent molecules. The present paper gives tire results of measurements of the free energies and heat contents of hydrogen chloride in water-alcohol solutions, obtained by determining the electromotive forces of cells of the type:— H 2 ( g ) | HCl ( m ), AgCl ( s ) | Ag water-alcohol

scholarly journals The behaviour of electrolytes in mixed solvents. Part. III.–The molecular refractivities and partial molar volumes of lithium chloride in water-ethyl alcohol solutions

1931 ◽  
Vol 131 (817) ◽  
pp. 382-390 ◽  
Keyword(s):  
Lithium Chloride ◽  
Ethyl Alcohol ◽  
Mixed Solvent ◽  
Mixed Solvents ◽  
Partial Molar Volumes ◽  
Ammonium Iodide ◽  
Dilute Aqueous Solutions ◽  
The Difference ◽  
Value Of It ◽  
Water Alcohol

It is well known that the molecular refractivity of most salts, as calculated by the Lorentz-Lorenz formula, is nearly independent of the concentration in moderately dilute aqueous solutions. Walden determined the refractivities of tetra-ethyl-ammonium iodide and other similar salts in a variety of solvents and found that, while the molecular refractivity was approximately independent of the concentration in each solvent, it varied from one solvent to another, the greatest variation from the value in water, amounting to about 2 per cent., being obtained in nitro-methane, Schreiner has recently determined the molecular refractivity of hydrogen chloride and lithium chloride in methyl and ethyl alcohols, and found that in the case of lithium chloride the value is independent of the concentration up to a concentration of about 3 M. His values for R 18 D for lithium chloride are: 8.73 in water, 8.55 in methyl alcohol and 8.38 in ethyl alcohol. The difference between the values in water and ethyl alcohol appeared to make it just possible to determine the variation of the refractivity with the composition of the solvent in mixtures of water and the alcohol. It is possible that a solvent might he found, miscible in water in all proportions, in which the value of It is further removed from that in water. Such a substance would he more suitable than alcohol for the investigation of this effect, but in order to correlate the results with the measurements recorded in Part II of the activities of alcohol and water in water-alcohol-lithium chloride solutions, it seemed desirable to investigate this case in the first instance. The variation of the refractivity of a salt with the composition of a mixed solvent may be expected to give some indication of the composition of the solvent in the immediate vicinity of the ions. For the refractivity of a salt is determined by (1) the polarisability of the ions themselves and (2) the change in the polarisability of the solvent produced by their presence. The molecular refractivity of a salt in a solution containing m grams of a salt in w grams of the solvent is taken as R = M/ m ( n 2 -1/ n 2 + 2 . w + m / d - n 2 0 -1/ n 2 0 + 2 . w / d 0 (1) where n , and d and n 0 , d 0 are the refractive index and density of the solution and of the solvent, respectively, and M the molecular weight of the salt.

scholarly journals The behaviour of electrolytes in mixed solvents. Part V.–The free energy of lithium chloride in water-alcohol mixtures and the salting-out of alcohol

1933 ◽  
Vol 141 (843) ◽  
pp. 86-94 ◽  
Keyword(s):  
Partial Pressure ◽  
Lithium Chloride ◽  
Mixed Solvents ◽  
Salting Out ◽  
Partial Pressures ◽  
All Solutions ◽  
The Mean ◽  
Alcohol Mixtures ◽  
Solvent Molecules ◽  
Water Alcohol

In Part II of this series of papers are recorded measurements of the partial vapour pressures of solutions of lithium chloride in water-ethyl alcohol mixtures, the alcohol contents of which extended from 6•4 to 100 mols. per cent. It has seemed desirable to extend this range so as to include some smaller concentra­tions of alcohol, and accordingly measurements have now been made of solutions containing 2 and 4 mols. per cent, of alcohol and in each case 0.5, 1.0 and 4.0 m. lithium chloride. The experimental method was the same as that previously described, except that in these cases the viscosity method was less suitable for determining the composition of the condensate, which was obtained by comparison with known compositions in the interferometer. The final values of the partial pressures, each being the mean of at least two deter­minations, are given in Table I. α w /α w 0 and α a /α a 0 are the relative activities, i. e ., the ratio of the partial pressure in a given solution to the partial pressure of the corresponding solvent. Two of the solutions containing 6.4 mols. per cent, alcohol were also redetermined and gave values in close agreement with those previously obtained. We are now in a position to discuss in more detail the behaviour of these solutions. It was shown in the previous paper that while the salt increased the partial pressure of alcohol in solutions containing smaller proportions of alcohol, it caused a lowering of the pressure in the more alcoholic solutions, but the relative lowering of the vapour pressure of alcohol was always less than that of water, indicating that in all solutions the alcohol was salted out with respect to the water. In order to assess this effect more precisely it is necessary to consider what will be the behaviour of a solute which interacts equally with the two solvent molecules.

scholarly journals The behaviour of electrolytes in mixed solvents. Part IV.—The free energy of zinc chloride in water-alcohol solutions

1932 ◽  
Vol 138 (835) ◽  
pp. 450-459 ◽  
Keyword(s):  
Free Energy ◽  
Hydrogen Chloride ◽  
Zinc Chloride ◽  
Electromotive Force ◽  
Mixed Solvents ◽  
Heat Content ◽  
Strong Electrolyte ◽  
Free Energies ◽  
Weak Electrolyte ◽  
Water Alcohol

In Part I of this series were described measurements of the free energy and heat content of hydrogen chloride in a series of water-alcohol mixtures. It appeared to be very desirable to find if the behaviour shown by hydrogen chloride is typical of that of strong electrolytes in general. For this purpose an attempt was made in the first place to determine the free energies of lithium chloride in these solvents, using amalgam electrodes. Preliminary measurements showed that even Under rigidly air-free conditions reproducible values of the electromotive forces of cells containing lithium amalgams could not be obtained in alcohol solutions. Similar experiences with sodium amalgams have been reported from the Balliol College Laboratory, while Scatchard has also experienced similar difficulties with calcium amalgams. It appeared that zinc chloride might be suitable, for when proper precautions are taken for the with zinc amalgam in aqueous solutions. The conductivities show that zinc chloride is a strong electrolyte in aqueous solution, and although several investigators have found that their product hydrolysed to give turbid solutions in water, we had no difficulty in obtaining a salt which gave perfectly clear solutions at all dilutions. The conductivity measurements of Getman and Gibbons, which show that in alcoholic solution zinc chloride is an extremely weak electrolyte, escaped our notice at the beginning of this work. But although on this account the behaviour of zinc chloride does not extend our knowledge of the properties of completely ionised substances in mixed solvents, it has proved to be an interesting case showing in the range of solvents investigated the transition from a strong to an exceedingly weak electrolyte. The free energies were determined by measuring the electromotive force of cells of the type Zn 1 percent. amalgam | ZnCl 2 , ( m ) Alcohol, N mols. per cent. AgCl( s ) | Ag The free energy change in the cell reaction, viz., Zn (Hg) + 2AgCl( s ) = ZnCl 2 ( m , N) + 2Ag, is given by ∆F = - 2 EF = - 46148E calories, where E is the electromotive force and F the electrochemical equivalent. The electromotive forces were determined in solvents containing 0, 25, 50, 90 and 100 mols. per cent, alcohol, each for a range of salt concentrations from about m = 0⋅01 to m = 1, at 15 ± 0⋅02°. It was originally intended to make a similar series of measurements also at 25°, in order to evaluate the heat content changes, but the reproducibility of the results in solutions containing large proportions of alcohol did not warrant this extension.

Activity Ratios of Lyate Ions in the Water-Alcohol Mixtures

1992 ◽  
Vol 57 (2) ◽  
pp. 255-262
Author(s):  
Zdeněk Pavelek ◽  
Jiří Mollin
Keyword(s):  
Experimental Determination ◽  
Activity Ratio ◽  
Mixed Solvents ◽  
Ion Transfer ◽  
Gibbs Energies ◽  
Activity Ratios ◽  
Alcohol Mixtures ◽  
The Individual ◽  
Water Alcohol

A new method for calculating the activity ratio of lyate ions in the water-alcohol mixtures is proposed on the basis of utilizing the linear relations between the Gibbs energies of ion transfer. The results for the water-methanol, -ethanol, and -2-propanol systems are compared with literature data. At the same time, the individual ionic products of water and alcohol in their mixtures were calculated. The accuracy of the method depends on the accuracy of experimental determination of the Gibbs energies of electrolyte transfer and of ionic products in mixed solvents.

Time-dependent Structure and Activity Changes of α-Chymotrypsin in Water/Alcohol Mixed Solvents

2000 ◽  
Vol 64 (12) ◽  
pp. 2552-2558 ◽  
Author(s):  
Makiko SATO ◽  
Toshiya SASAKI ◽  
Masami KOBAYASHI ◽  
Hideo KISE
Keyword(s):  
Mixed Solvents ◽  
Time Dependent ◽  
Structure And Activity ◽  
Water Alcohol
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