To determine if a reaction is second-order, one can perform experiments by varying the concentrations of the reactants and measuring the reaction rate. The data can then be plotted, and if the plot of \( \frac{1}{[\text{A}]} \) vs. time yields a straight line, the reaction is second-order. Additionally, techniques like spectroscopy and chromatography can be used to monitor the concentrations of reactants and products over time.