Ion-Pair Association Constants of Alkali & Alkaline Earth Metal Formates in Formic Acid-Acetonitrile Mixtures at 30°C-A Conductance Study

Abstract

Equivalent conductance values of solutions of lithium, sodium, potassium, calcium and barium formates in 20% formic acid + 80% acetonitrile and 80% formic acid + 20% acetonitrile mixtures have been determined at different concentrations. Fuoss-Kraus and Shediovsky extrapolation methods are used to determine ion-pair association constants (<em>K</em>_a). Reasonable agreement is found between the <em>K</em>_a values obtained by the two methods. Experimentally obtained ion-pair association constants are compared with those calculated using Bjerrum (B), Fuoss (F), Denison &amp; Ramsey (DR) and Ebeling-Kraeft-Yokoyama-Yamatera (EKYY) theories. The results are used to arrive at the type of the ion-pairs and to establish the nature of the ion-solvent interaction.