Electron Transfer in Fe + HCl Reaction: How Many Electrons are Involved?

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Discussion Overview

The discussion revolves around the electron transfer involved in the reaction between iron (Fe) and hydrochloric acid (HCl), specifically the equation Fe + 2HCl -> FeCl2 + H2. Participants explore how to determine the number of electrons transferred during this reaction, examining half-reactions for oxidation and reduction processes.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant suggests using a reduction potential table to analyze the reaction, questioning whether to consider the reactions involving H and Cl first.
  • Another participant recommends splitting the reaction into half-reactions for oxidation and reduction to clarify the electron transfer process.
  • Concerns are raised about the placement of electrons in the half-reactions, with a participant noting that both reactions appear to have electrons on the right side, leading to confusion about the total electron transfer.
  • A participant emphasizes the need to reverse one of the half-reactions since the reaction does not start with Fe2+, which is crucial for determining the correct electron transfer.
  • It is noted that Fe is oxidized in the reaction, and participants discuss the implications for the net ionic reaction to identify what is being reduced.

Areas of Agreement / Disagreement

Participants express differing views on how to approach the analysis of the reaction, particularly regarding the use of half-reactions and the placement of electrons. There is no consensus on the correct method to determine the number of electrons transferred.

Contextual Notes

Participants highlight the importance of starting conditions and the need to reverse reactions in the context of half-reactions, indicating potential limitations in their current understanding of the electron transfer process.

mate1000
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Hey iv been given a tutorial question that says:
How many electrons are transferred in the following reaction?

Fe + 2HCl -> FeCl2 + H2

Now when you go to a redution potential table and get
Fe2+ + 2e- -> Fe(s)
2H+ + 2e- -> H2
Cl2 + 2e- -> 2Cl-

Do you have to do the reaction between the H and Cl first and then do the whole reaction or what?
Cheers
 
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Forget about table, try to split the reaction into two half reactions - reduction and oxidation.
 
If you look at the half reactions though don't both reactions have the electrons on the right hand side in order to get the right final equation, or am i missing something crucial out.
But if Fe is oxidation Fe-Fe2+ + 2e- and Cl is reduction Cl2 + 2e- - 2Cl-, then u would have a transfer of two electrons, right?
 
mate1000 said:
If you look at the half reactions though don't both reactions have the electrons on the right hand side in order to get the right final equation, or am i missing something crucial out.

What you are missing is fact, that you don't start wirh Fe2+ - so you have to reverse one of the reactions.

But if Fe is oxidation Fe-Fe2+ + 2e- and Cl is reduction Cl2 + 2e- - 2Cl-, then u would have a transfer of two electrons, right?

Fe is oxidized, that's OK.

Write net ionic reaction, you will see what is being reduced.
 

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