THE CLOCK BEHAVIOR OF THE BRO3--SCN- REACTION

The dynamics of the BrO3--SCN- reaction in an HClO4 medium has been st udied using the stopped-flow method. Production of bromine in the syst em follows a sigmoidal course with two induction periods (low acidity conditions). Under conditions of higher acidity the bromine concentrat ion passes through a maximum, while the first induction period (lag ph ase) is preserved, though it becomes very short. The effect of H+ and SCN- ions on the lag phase was quantitatively investigated. A simple k inetic model based on four component processes is proposed. Simulation s are in good agreement with experiments. The dynamics of the BrO3--SC N- reaction under conditions of a closed reactor may be understood as clock behavior.