The reaction between IO4- and S2O32- exhibits a variable stoichiometry in acetate buffer. With a large excess of IO4-, the products are IO3- and SO42-. In excess thiosulfate, IO4- is reduced to I-, and S4O62- is formed in addition to SO42-. The ratio of S4O62- increases with decreasing pH. In a flow reactor at high input concentrations, when the flow rate or temperature is changed or small amounts of a reactant are injected, an unbuffered reaction mixture initially in a steady state shows a strongly damped oscillatory response in pH and redox potential. At lower input concentrations, sustained pH oscillation is found. A simple model, consisting of an autocatalytic hydrogen ion production and a linear H+ consumption, allows accurate simulation of all of these kinetic behaviors.
ASJC Scopus subject areas
- Physical and Theoretical Chemistry