Study of cyanoaquonitrosyl complex of chromium. II. Acid hydrolysis of [Cr(CN) 2(H 2O) 3NO]: an example of a solution of two-step kinetics of successive one-directional first-order reactions with unknown intermediate properties

Abstract

A procedure for evaluation and calculation of the rate constants for a direct two-step chemical reaction using the time-dependence of an analytical property proportional to the intermediate concentration is described. The method does not require that the intermediate properties be known. The calculation is demonstrated employing the absorbance as the analytical property. The method proposed is applied to the spectrophotometric study of the kinetics of hydrolysis of [Cr(CN) 2H 2O) 3NO] in a strongly acid medium (0.025–2 M HClO 4). The rate and the protonation equilibrium constants for the hydrolytic steps and the activation parameters are given and the hydrolyric scheme is postulated.