H2O2 + KI (Hydrogen peroxide + Potassium iodide) HD

H2O2 (hydrogen perioxide) will decompose into H2O and O2 on its own, albeit slowly. One reason H2O2 comes in dark bottles is to slow this process, which is accelerated by light. To catalyze, or speed up the reaction, we can add KI (Potassium iodide) to the H2O2. The KI isn’t changed as a result of the reaction and is not considered a reactant. Instead, we write KI above the “yields” arrow to show that it served as a catalyst in the reaction. There is also an enzyme in your blood called catalase. That is why you see bubbles when you put H2O2 on a wound. The bubbles are O2 gas. Note that enzymes are considered biological catalysts. KI Image: Public Domain, https://commons.wikimedia.org/w/index.php?curid=184594