The Kinetics of the Rapid Gas Reaction between Ozone and Nitrogen Dioxide

An apparatus has been designed and constructed which will rapidly mix two gaseous reactants, isolate them in a reaction cell, and, by means of light absorption, follow the course of the reaction photoelectrically in one‐tenth of a second or less. The output of the photoelectric tube is recorded by a time‐exposure photograph of the screen of an oscilloscope. The kinetics of the fast reaction between ozone and nitrogen dioxide was studied over a tenfold range of concentration of each reactant. The rate law was found to be $$\mathrm{-d(}{\mathrm{O}}_3\mathrm{)/dt=k(}{\mathrm{NO}}_2\mathrm{)(}{\mathrm{O}}_3)$$ over the entire course of the reaction. From the temperature coefficient of the rate of reaction the energy of activation was found to be 7.0±0.6 kilo‐calories per mole. A mechanism is proposed to account for the observations.