Why Is the Potential of the Hydrogen Electrode Not Zero?

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Discussion Overview

The discussion revolves around the concept of the standard hydrogen electrode and its potential, specifically addressing why the potential of the hydrogen electrode is sometimes considered to be non-zero. Participants explore definitions and implications of standard electrodes and potentials in the context of electrochemistry.

Discussion Character

  • Homework-related
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • One participant notes confusion regarding the potential of the hydrogen electrode, stating it is typically considered standard and thus should be zero.
  • Another participant questions the meaning of "standard electrode" and "standard potential," seeking clarification on these terms.
  • Some participants propose that the hydrogen electrode could be non-standard due to unknown solution molarity, suggesting this could lead to a non-zero potential.
  • There is a discussion about the definition of standard potential, with one participant suggesting it relates to the reducing strengths of other electrodes relative to the standard hydrogen electrode.
  • A later reply emphasizes that standard potential requires the system to be in the standard state, indicating a potential limitation in the earlier definitions provided.

Areas of Agreement / Disagreement

Participants express uncertainty and differing interpretations regarding the definitions and implications of standard potential, indicating that multiple competing views remain without a clear consensus.

Contextual Notes

There are limitations in the discussion regarding the assumptions about the standard state and the specific conditions under which the hydrogen electrode's potential is evaluated. The definitions provided by participants vary and may depend on context.

TT0
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Homework Statement


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Homework Equations

The Attempt at a Solution


From the calculation of the potential of the cell and the potential for the copper electrode, it states that the hydrogen electrode has a potential of -0.09 V. But I thought hydrogen electrode is standard so it should be zero. Therefore I am not sure between C and D. Can someone explain which one is right and why?

Cheers!
 
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TT0 said:
But I thought hydrogen electrode is standard so it should be zero.

What does it mean "standard electrode"? What does it mean "standard potential"?
 
Standard electrode is a standard hydrogen electrode. Standard potential is the difference in voltage between the standard hydrogen electrode and the concerning electrode. I guess the hydrogen electrode could be non standard as you don't know it's solution's molarity and what M is. This means the answer is D?

Cheers!
 
TT0 said:
Standard electrode is a standard hydrogen electrode. Standard potential is the difference in voltage between the standard hydrogen electrode and the concerning electrode.

"Standard is a standard" is a tautology and it doesn't add much to the problem.

What is the definition of the standard potential?

Actually it seems like you are aware of what is important here, but you failed to mention it correctly.
 
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What is the definition of the standard potential?
I am not too sure. I think standard potential is the reducing strengths of the other electrodes relative to the standard hydrogen electrode.
 
TT0 said:
I am not too sure.

Then google it, or check your notes, or the book.
 
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Standard potential is the measure of the energy per unit charge which is available from the oxidation/reduction reactions of each electrode relative to the standard hydrogen electrode. So as the hydrogen electrode is not the standard one, it's reduction potential can be non-zero so D is the answer?

Cheers!
 
Sadly, this definition doesn't touch on a very important point - standard potential requires the system to be in the standard state.
 
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I see, thanks!
 

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