👉 In chemistry, an oxidiser is a substance that can be used as an oxidant, which means it can act as a catalyst in chemical reactions. Oxidizing substances are those that donate electrons to other molecules, and they can react with certain compounds to form products that can be useful in various chemical processes. Examples of oxidisers include: - Oxygen (O2) - Nitrogen (N2) - Carbon dioxide (CO2) - Water (H2O) - Iron (Fe