Salting-Out

The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.

Salting-Out

 

the liberation of a dissolved substance from solution by the addition of another substance (usually a salt) with greater solubility.

Two instances of salting-out are differentiated: (1) salting-out of electrolytes by electrolytes, and (2) salting-out of nonelectrolytes by electrolytes. In the first case the electrolyte used for salting-out has the same ion as the substance salted out. Thus, sodium chloride (NaCl) can be displaced from an aqueous solution by magnesium chloride (MgCl2). Here the solubility product gives a quantitative estimate. In the second case the substance used for salting-out unites with the solvent, thus in effect reducing the amount of solvent for the substance being salted out. Salting-out is used both in analytical chemistry and in industrial chemistry (salting-out of soap or dyes; in radiochemistry, the chlorides of barium and radium, BaCl2 and RaCl2, are salted out by the addition of hydrochloric acid, HC1).

The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.