The Pressure Effect on Conductances of KCl in Ethanol–Water Mixtures at 25 °C

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Abstract
The molar conductances of KCl in 5, 10, 15, 20, and 30 mol% ethanol–water mixtures were measured in the dilute concentration range of (2–8)×10−4 M (1 M=1 mol dm−3) at 25 °C up to 1500 kgf cm−2 (1 kgf cm−2=0.9807×105 Pa). The Fuoss-Onsager conductance equation for unassociated electrolytes was used to determine the limiting molar conductance, Λ°, of KCl in 5 and 10 mol% of ethanol. In 15, 20, and 30 mol% of ethanol, where the ionic association takes place, the Shedlovsky equation was employed to obtain Λ° and the association constant KA of KCl. The limiting ionic molar conductances of the K+ and Cl− ions were determined by combining Λ° with the limiting transference number for KCl. The Walden products of both K+ and Cl− ions decrease with an increase in the pressure in 5 mol% of ethanol, but in 15 mol% of ethanol and above they increase with an increase in the pressure. These facts indicate that the breaking effect of these ions appears prominently in about 5 mol% of ethanol.