OSCILLATORY DECOMPOSITION OF H<inf>2</inf>O<inf>2</inf> MONITORED BY THE POTENTIOMETRIC METHOD WITH Pt AND Ag⁺ /S^{2 -} INDICATOR ELECTRODE

Abstract

The oscillatory decomposition of hydrogen peroxide in the presence of potassium iodate and sulphuric acid is analysed potentiometrically with the aid of Pt and Ag** plus /S**2** minus electrodes. Data pertaining to the concentration changes of iodide and hydrogen peroxide and to the oxido-reduction evolution of the system in its various characteristic states are thus obtained. It is established that the concentration ratio of these two substances is approximately constant at the boundaries of the oscillatory range when the concentration of the hydrogen peroxide in the system exceeds the value necessary for regular oscillations. The rate constant of the disappearance of iodide in the system in the region of smooth catalysis is somewhat smaller than rate constant of the overall decomposition of the hydrogen peroxide.