The Systems Lithium Chloride-Water-Ethyl Alcohol and Lithium Bromide-Water-Ethyl Alcohol1,2

1936 ◽  
Vol 58 (9) ◽  
pp. 1692-1695 ◽  
Author(s):  
John P. Simmons ◽  
Henry Freimuth ◽  
Harry Russell
Keyword(s):  
Lithium Chloride ◽  
Ethyl Alcohol ◽  
Lithium Bromide ◽  
Chloride Water

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.

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