The presence of a catalyst in a chemical reaction, such as the reaction between hydrogen peroxide H2O2 and potassium iodide KI , significantly increases the rate of the reaction without being consumed in the process.In the reaction between hydrogen peroxide and potassium iodide, the hydrogen peroxide decomposes into water and oxygen gas, while the iodide ions I- are oxidized to iodine I2 . The overall reaction can be represented as:2H2O2 aq 2H2O l + O2 g The presence of a catalyst, such as potassium iodide, speeds up this reaction by providing an alternative reaction pathway with a lower activation energy. This means that a larger proportion of the reacting molecules have enough energy to overcome the energy barrier and react, leading to a faster reaction rate.In this specific reaction, the iodide ions I- from potassium iodide act as a catalyst. They react with hydrogen peroxide to form water and iodine I2 , and then the iodine reacts with more hydrogen peroxide to regenerate the iodide ions and produce oxygen gas. The net result is the decomposition of hydrogen peroxide into water and oxygen gas, with the iodide ions acting as a catalyst to speed up the reaction.To summarize, the presence of a catalyst, such as potassium iodide, in the reaction between hydrogen peroxide and potassium iodide significantly increases the rate of the reaction by providing an alternative reaction pathway with a lower activation energy, allowing more molecules to react and speeding up the overall reaction.