On the catalytic influence of the reaction‐products on the speed of decomposition of chromic acid in solutions of sulphur trioxide in water

Abstract

AbstractThe speed of decomposition of solutions of chromic acid in strong (e.g. 100%) sulphuric acid is reduced by the product of the reaction, a nearly colourless substance which precipitates when its solution is heated.The formation of this precipitate and the reduction of the speed of reaction may be observed also when a slight amount of water is present, both effects increasing with increasing sulphuric acid content.A positive autocatalytic effect in more diluted sulphuric acid is already known H. C. S. Snethlage. Rec. trav. chim. 55, 874 (1936). .In combination with the hypothesis which was developed for the explanation of the variations of the speed of decomposition, which result from a change in the composition of the solventH. C. S. Snethlage, Rec. trav. chim. 55, 712 (1936). .), these two catalytic effects allow the understanding of the behaviour of decomposing solutions of chromic acid at any composition of the solvent (at least above 60% acid) and at any stage of the decomposition.