Using integrated rate equations for determine the order of a reaction

The reaction under study is performed by taking different initial concentrations of the reactant (a) and noting the concentration (a–x) after regular time intervals (t). The experimental values of a (a– x) and tare then substituted into the integrated rate equations for the first, second and third order reactions. The rate equation which yields a constant value of k corresponds to the correct order of the reaction. This method of ascertaining the order of a reaction is essentially a method of hit and-trial but was the first to be employed. It is still used extensively to find the order of simple reactions.