Transport parameters of LiCl and LiBr in aqueous mixtures with organic solvents of moderate to low permittivities

The electromotive forces (emf) EA and EC of the following concn. cells with transference: Ag|AgX|LiX(m2)||LiX(m1)|AgX|Ag and LixHg1-x|LiX(m1)||LiX(m2)|LixHg1-x, resp. (where X = Cl, Br), combined with the emfs EMAX of the corresponding double cell without transference: LixHg1-x|LiX(m1)|AgX|Ag-Ag|AgX|LiX(m2)|LixHg1-x have been measured at LiX molalities m (m1 fixed and m2 varied, with m2 > m1) in 14 solvent mixts. pertaining to the three aq.-org. solvent systems (acetonitrile + water), (1,4-dioxane + water) and (methanol + water) up to the 0.8 mass fraction of org. component. For all of the cases studied the EA vs. EMAX relation is a curve reaching a straight line asymptotically at low LiX molalities. The resulting ionic transference nos. t of LiX show a type of curvilinear dependence on the mass fraction of the org. component which shows analogies with that of the other alkali halides hitherto studied, but is quite distinct from that of HCl. Such a dependence is also analyzed in terms of solvation parameters and the mechanism of ionic motion, with account being taken of Stokes' law ionic radii.