Periodic Convection in the Bromate-Sulfite Reaction: A "Jumping" Wave

Abstract

An unusual spatiotemporal phenomenon was observed in propagating fronts in the bromate‐sulfite system with an initial pH gradient, but not in chlorate‐sulfite nor iodate‐sulfite systems. Periodic acceleration and deceleration of the front were observed, which appeared as a "jumping" wave. An experimental method was developed to produce the pH gradient systematically and reproducibly in a tube. The effect of the gradient was studied. With the use of infrared and visible imaging the competition between chemically and thermally induced convection was observed. A qualitative model is proposed that includes the effect of pH gradint and the specific mechanism of the bromate oxidation of sulfite.