Dependence of the inflection time on the initial concentrations in autocatalytic reactions. Maxima, minima and ‘anomalous changes’

Abstract

The existence and the behaviour of the inflection time (the turning-point in the rate–time dependence) has been investigated as a function of the initial concentrations of the components in autocatalytic reactions. For a group of rate equations it is shown that the inflection time is a strictly decreasing function of the initial concentration of the autocatalyst. When the initial concentration of the autocatalyst is fixed, the inflection time may attain maxima and minima or may be everywhere increasing with increasing initial concentration of the subtrate. The difference in the influence of the two components remains even when the rate equation is symmetric. Examples and some practical consequences are discussed.