Graphical method for determine the order of a reaction

For reactions of the type A →products, we can determine the reaction order by seeing whether a graph of the data fits one of the integrated rate equations.

In case of First order

We have already derived the integrated rate equation for first order as

Hence, if 1n a/a–x is plotted against tand straight line results (Fig. 1.1), the corresponding reaction is of the first order. However, if a curve is obtained, the reaction is not first order.

We have already shown that second order rate equation can be written as

Thus when  1 / a−x is plotted against t and we get a straight line (Fig. 1.2), the reaction is second order. In case a curve is obtained, the reaction is not second order