A theory of electro-kinetic effects in solution; reactions between ions and polar molecules

Abstract

The experimental values of the velocity coefficient k for bimolecular reactions may be summarized in an equation of the form k = Z . P . e -E A /RT (1) where P and E A are empirical constants, specific for each reacting system, and Z is the kinetic theory value for the frequency of binary collisions, namely, Z = N 0 /1000 r 1,2 2 n 1 n 2 { 8π k T (1/m 1 + 1/m 2 )}. (2) The physical significance of the term P may be realized by considering the hypothetical case where the Arrhenius energy of activation E A is identical with the true energy of activation E'. Since the theoretical expression for the maximum velocity of the bimolecular process is k = Z . e -E'/RT , (3) it is seen that P measures the absolute probability that a binary collision of sufficient energy leads to chemical reaction. In general, however, E A and E' are not identical, and the interpretation of the term P is not so simple.