Thermodynamic functions of activation of ion-molecule reactions in alcohol-water mixtures over composition and temperature ranges — I. A study of the (un-monitored) conductimetric technique used by Iskander and others for evaluating the second-order rate constant of alkaline hydrolysis reactions

Abstract

The unmonitored conductimetric technique, which had been used by Iskander, Wasif and Tewfik[3] for determining the second-order rate constant (k 2) of the alkaline hydrolysis of ethyl benzoate and of ethyl p-nitrobenzoate in ethanol-water mixtures, has been initially used in this study to extend those measurements to other solvent compositions and temperatutes. Unfortunately, it has been found that the technique, as applied by those workers, can lead to ambiguous or inaccurate k 2 values. Consequently, their results for the two esters are found to deviate markedly from those obtained in other laboratories using more direct titrimetric methods. Some of the possible causes of failure of the former technique have been examined. The k 2 values for the two esters have been re-evaluated using our pH-titration technique described elsewhere[4].