Which Substance in Blood Catalyzes Hydrogen Peroxide Decomposition?

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Discussion Overview

The discussion revolves around identifying which substance present in blood catalyzes the decomposition of hydrogen peroxide (H2O2). Participants explore various chemical compounds, including manganese and iron compounds, and the enzyme catalase, while considering the context of a high school laboratory setting.

Discussion Character

  • Exploratory
  • Debate/contested
  • Homework-related

Main Points Raised

  • One participant notes that manganese dioxide (MnO2) is commonly cited as a catalyst for H2O2, but questions arise regarding the role of potassium permanganate (KMnO4) since it appears to change during the reaction.
  • Another participant suggests that any manganese ion in a positive oxidation state, such as Mn4+ or Mn7+, could act as a catalyst, though they express uncertainty about this claim.
  • A participant asserts that none of the listed substances (MnO2, KMnO4, FeCl3, Fe(NO3)3) are present in blood, emphasizing that catalase is the known catalyst for H2O2 decomposition.
  • One participant agrees with the previous point and mentions that the lab protocol may have oversimplified the situation, expressing frustration about the limitations of their knowledge at the high school level.
  • Another participant humorously suggests simply writing "catalase" as the answer, while cautioning against facetious responses.
  • A participant points out that catalase contains four iron-containing heme subunits, linking it to the discussion of iron compounds.
  • One participant expresses hesitation between choosing MnO2 and KMnO4 due to a lack of justification for their hypothesis, indicating a struggle to select a specific compound.
  • Another participant claims that both iron chloride and iron nitrate can catalyze the decomposition of peroxide, sharing a personal experience with ferric chloride in a practical application.

Areas of Agreement / Disagreement

Participants generally agree that catalase is the enzyme responsible for catalyzing H2O2 decomposition in blood. However, there is disagreement regarding the relevance and presence of the other listed substances, with some participants asserting they are not found in blood while others explore their potential catalytic roles.

Contextual Notes

Participants express limitations in their knowledge and the context of their high school lab, which may restrict their ability to fully explore the topic. There is also uncertainty regarding the presence of certain compounds in blood and their catalytic properties.

alingy1
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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?
 
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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.
 
alingy1 said:
I've been asked to find which substance present in blood is the catalyser of H2O2:
-MnO2
-KMnO4
-FeCl3
-Fe(NO3)3

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

For the components of blood, I could only find that the enzyme catalase was the catalyser.

That would be my answer.
 
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. :confused:
 
Sadly, you are put in a no win situation then.
 
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.
 
catalase has four iron-containing heme subunits.
 
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? :frown:
 
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.
 

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