Transference numbers of NaCl in aqueous mixtures with organic solvents of moderate to low permittivities

Electromotive forces (emf) were measured in the transference cells: Ag|AgCl|-NaCl (m2) in Z|| NaCl (m1) in Z|AgCl|Ag and NaxHg1-x|NaCl(m1) in Z|| NaCl (m2) in Z|NaxHg1-x (where NaxHg1-x denotes a flowing Na-amalgam electrode and Z an aq.-org. solvent mixt.) at various molalities m2>m1 of NaCl in Z=(ethylene glycol + water), (acetonitrile + water) and (1,4-dioxane + water), with mass fractions of the org. components ≤0.8. The transference no. of Na+ in (ethylene glycol + water) and (1,4-dioxane + water) varies little with respect to that in pure water medium, whereas in (acetonitrile + water) it increases remarkably with increasing proportion of acetonitrile so as to approach equitransference, behavior similar to that previously found in (methanol + water) and in (ethanol + water). At acetonitrile mass fraction 0.6 NaCl is sufficiently close to equitransference to emerge a a useful salt bridge, nearly at the same level as the popular aq. KCl.