Catalyser of hydrogen peroxide

alingy1

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?

Big-Daddy

I think that any ion with Mn in a positive oxidation state will do the trick, so Mn⁴⁺ will be effective and so will Mn⁷⁺. I could be wrong here though.

Borek

Generally speaking, none of these substances is present in blood.

That would be my answer.

alingy1

I agree with you. I researched it and found none of these in blood. I think they entirely simplified the protocole for my lab. (I am in high school by the way.) Unfortunately, I can't really put the enzyme because we're not supposed to know that by now. It is indubitably hard to form a hypothesis.

Borek

Sadly, you are put in a no win situation then.

epenguin

Just write 'catalase'. You found out about it. :)

It could go against you if you wrote any of the facetious answers that came to my mind about not being supposed to know about anything, so don't.

chemisttree

catalase has four iron-containing heme subunits.

alingy1

Logically, I would put catalyse. However, staying in the context of the lab, I don't know which one to chose. I'm hesitating between MnO2 and KMnO4. Unfortunately, I can't really justify my hypothesis, plus I have to chose one specific compound. What should I do?

chemisttree

iron chloride and iron nitrate both catalyze the decomposition of peroxide. I have used ferric chloride to render safe for disposal a rather large quantity of 30% peroxide. Any transition metal decomposes it and you must take precautions against contaminating stock solutions of peroxides.