Trigger Waves in the Acidic Bromate Oxidation of Ferroin
نویسنده
چکیده
The acidic bromate oxidation of ferroin in batch reaction proceeds with slow consumption of bromide until a critical bromide concentration is attained. At that point ferroin is suddenly oxidized to ferriin in a process involving autocatalytic generation of bromous acid. Prior to the transition, in an unstirred thin film of solution, a single trigger wave of chemical reactivity may develop and subsequently propagate, converting the reaction mixture from the reduced state to the oxidized state. Because the reaction is nonoscillatory, the trigger wave represents a propagating front. Waves were electrochemically initiated by local depletion of bromide and effects of reactant concentrations on propagation velocity were investigated. The dependence of wave velocity on [Br-] ahead of the advancing wave was investigated and the critical bromide concentration for wave propagation, [Br-I,,, was determined. The coexistence of kinetic states and spatial bistability are considered.
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