Transference numbers for anhydrous methanol solutions at 10 and 25°C

Transference numbers are reported for LiCl and NaCl in methanol at 25°C and for NaCl, KCl, and Bu₄NBr in methanol at 10°C. The potentiometric moving-boundary method as developed by Kay and Fratiello was employed to give a precision of about 0.05% and an accuracy of at least 0.1% as indicated by two independent determinations of the conductances of the Cl^– and Br^– ions. The data are extrapolated by the Fuoss-Onsager theory, and the magnitude of the electrophoretic effect is calculated as described by Kay and Dye. The agreement with this theory is quite good at both temperatures, although the å value required in the case of Bu₄NBr is considerably larger than that obtained from conductance data. This agreement contrasts with that obtained for ethanol and acetone solutions where the measured electrophoretic effect is considerably larger than the corresponding calculated values. The importance of this fact in the determination of ion-pair association constants is discussed.