Water transport in aqueous organic solvents. Dimethyl sulphoxide + water + hydrochloric acid at 25°C

Abstract

An e.m.f. method has been used to determine, (a) the molar transport number, or Washburn number, tw, of water in dimethyl sulphoxide + water mixtures containing hydrochloric acid and (b) the transport numbers of hydrochloric acid in these solvent mixtures. Within the composition range studied [up to 40 %(w/w) dimethyl sulphoxide], tw shows a pronounced variation with solvent composition, passing through a maximum at 10–20 % dimethyl sulphoxide. These features are discussed in terms of the effects of solvent structure and ion-solvent interactions on the transport of water by the ions.