Hello fellow scientists! I'm confronted to this conundrum: I've been asked to find which substance present in blood is the catalyser of H2O2: -MnO2 -KMnO4 -FeCl3 -Fe(NO3)3 I've thought about it for a long time. However, it is said that MnO2 is a catalyser of H2O2 online. Then, I have seen a video that shows the reaction with KMnO4. That reaction is very fast. However, in the video, the chemical equation shows that KMnO4 is no longer KMnO4 at the end, which contradicts the whole concept of a catalyser. I know that iron can be found in blood. For the components of blood, I could only find that the enzyme catalase was the catalyser. I'm a bit mixed up. Can you please clarify this?