The Kinetics of the Reduction, in Acid Solution, of Hydrogen Peroxide by Iodide Ion

Abstract

1. The rate of the reaction [formula omitted] has for the first time been measured under the simplest experimental conditions, with the result that the law, previously established [formula omitted] has been formally corroborated. Accurate values of k1 can now be given. 2. The simplest kinetic interpretation of this rate law assumes the ratedetermining steps [formula omitted] to proceed simultaneously and independently. At 25°, k°1 = 0.69 and k1 = 10.5; these measured values probably do not differ by more than 1% from the true values of these specific rates. 3. An examination of the early work of Magnanini2 shows it to be in excellent agreement with our results. Certain trends in his rate measurements have been explained. 4. Within the ionic strength range investigated (roughly, from μc = 0.05 to 0.5) Reaction 4 is without appreciable kinetic salt effect. 5. We have found [formula omitted] Over the temperature ranges investigated, these equations give to within 3% the values of the specific rates. By use of an approximate method, the details of which are described, we have calculated the average error in Q°1 to be 105, and that in Q1, 120 calories. 6. A brief discussion of the variation with temperature to be expected for the apparent heats of activation of reactions in aqueous solution has been given. © 1933, American Chemical Society. All rights reserved.