Transference numbers for magnesium chloride at 25°C

Abstract

Transference numbers for aqueous magnesium chloride at 25°C have been measured by the moving-boundary method at concentrations up to 0.5 molar. The boundary movement was followed by using a newly designed radiofrequency detector by means of which the boundary velocity was determined by its passage past wire electrodes wrapped around the external surface of the moving-boundary tube. Extrapolation to infinite dilution gives T^+/₀ (MgCl₂, 25°C) = 0.4114 which when combined with the known limiting conductance for the chloride ion gives the following equivalent conductances: Λ₀ (MgCl₂, 25°C) = 129.7₈ and l.₀ (Mg²⁺, 25°C) = 53.3₉. Both of these values are independent of conductance measurements on MgCl₂ but are shown to be consistent with the latest conductance data for MgCl₂.