Irrelevance of gas evolution to oscillations in the Belousov–Zhabotinsky system

Abstract

A Belousov–Zhabotinsky system containing malonic acid substrate and cerous ion catalyst oscillates at almost the same frequency whether it is stirred gently, so that most of the solution has no contact with air, or whether it is frothed by a vigorous stream of small bubbles of nitrogen which would rapidly entrain any dissolved gas. This observation supports the generally held opinion that oscillations in Belousov–Zhabotinsky systems are generated by homogeneous chemical processes. It refutes a recent proposal that these oscillations result when gas bubbles are nucleated in supersaturated solution.