The use of a catalyst affects the rate of a chemical reaction by increasing the reaction rate without being consumed in the process. Catalysts work by providing an alternative reaction pathway with a lower activation energy, which allows more reactant molecules to have enough energy to undergo the reaction. As a result, the reaction proceeds more quickly.Experimental evidence supporting the effect of catalysts on reaction rates can be found in numerous studies and experiments. One classic example is the decomposition of hydrogen peroxide H2O2 into water H2O and oxygen O2 . This reaction occurs naturally but at a slow rate. However, when a catalyst such as manganese dioxide MnO2 or potassium iodide KI is added, the reaction rate increases significantly, and oxygen gas is produced more rapidly.In an experiment, you can set up two separate containers with equal amounts of hydrogen peroxide solution. Add a catalyst e.g., manganese dioxide to one container and leave the other one as a control without any catalyst. You can then measure the rate of oxygen gas production in both containers by collecting the gas in an inverted graduated cylinder or burette filled with water. The container with the catalyst will produce oxygen gas at a much faster rate than the control, demonstrating the effect of the catalyst on the reaction rate.This experiment, along with many others, provides clear evidence that catalysts can significantly increase the rate of chemical reactions without being consumed in the process.