TRANSFERENCE NUMBERS OF CONCENTRATED ELECTROLYTES AND CHARACTERIZATION OF SALT BRIDGES IN THE ETHANOL PLUS WATER SOLVENT MIXTURES

Electromotive force measurements have been made using the transference cells: Ag\AgCl\MCl (m(2))\MCl (m(1))\AgCl\Ag and M(Hg)MCl (m(1))\MCl (m(2))\M(Hg) (where M = Na, K, and Cs and M(Hg) denotes a flowing M-am algam electrode) at various molalities m(2) > m(1) of MCl salts in eth anol (1) + water (2) with ethanol mass fraction omega(1) up to 0.8. Th e results indicate that the ions in CsCl have approximately equal tran sference number from pure water up to omega(1) = 0.6 for ethanol, but at omega(1) = 0.7 the transference numbers of the ions start to differ . Also, the transference numbers of the ions in KCl in ethanol + water approach 0.5, but at omega(1) > 0.4, the KCl solubility becomes insuf ficient for a salt bridge function. NaCl, which is not good as a salt bridge in water, is more useful with increasing ethanol concentrations , and the transference numbers of the ions approach 0.5 at ethanol mas s fraction omega(1) > 0.8.