Voltaic Cell behaviour as described in this video

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Discussion Overview

The discussion revolves around the behavior of a Voltaic cell as presented in a video, specifically focusing on the reactions occurring at the Copper half-cell when no external electrical conductor is connected. Participants explore the implications of the reactions and the conditions under which they occur.

Discussion Character

  • Debate/contested
  • Technical explanation
  • Conceptual clarification

Main Points Raised

  • One participant questions the accuracy of the video, noting that it suggests Copper atoms oxidize to form Cu++ cations while losing electrons, which contradicts their understanding of the reduction process at the Cathode when an external connection is present.
  • Another participant raises a question about the necessity of copper ions in solution for reduction to occur, suggesting that the direction of the reaction may be limited by the presence of these ions.
  • A subsequent post emphasizes the importance of the initial conditions at the Copper half-cell and seeks confirmation that copper cations in solution would be reduced, resulting in a positively charged Copper rod without an external connection.
  • One participant expresses skepticism about the video's clarity, suggesting it oversimplifies the processes involved in the Voltaic cell.
  • Another participant supports the idea that, under ideal conditions, the expected reaction at the Copper half-cell would lead to the reduction of copper cations.
  • A participant argues against the necessity of invoking charge separations, stating that zinc atoms will transfer electrons to copper ions when in contact, regardless of direct electrical connection, as long as a return pathway for electrons exists.
  • In response, another participant asserts that without charge separation, there can be no potential difference, indicating that charge considerations are essential to understanding the physics involved.

Areas of Agreement / Disagreement

Participants express differing views on the accuracy of the video and the conditions necessary for the reactions at the Copper half-cell. There is no consensus on the correctness of the video's portrayal of the reactions or the role of charge separation in the process.

Contextual Notes

Participants highlight the complexity of the reactions and the potential for misunderstanding due to simplifications in the video. The discussion reflects uncertainty regarding the initial conditions and the assumptions about ion presence in solution.

cianfa72
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TL;DR
Voltaic cell behavior with no external connection
Hi,

googling for Voltaic cell I found this video about it. At minute 2:35 to 2:54 you can see that, without any electrical conductor connected between electrodes, in the Copper half-cell the metal electrode (Cathode) gets an amount of negative charges (electrons). Basically what described there is that Copper atoms oxidize passing in solution as Cu++ cations loosing electrons inside the Copper electrode.

As far as I Know actually, at least when an external connection is in place, the opposite reaction (Copper ions reduction) should take place at the Cathode electrode.

Do you think that video is correct ? Thanks.
 
Last edited:
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If there are no copper ions on the solution, can they get reduced? Or are the options of in which direction reaction can proceed limited?
 
Borek said:
If there are no copper ions on the solution, can they get reduced? Or are the options of in which direction reaction can proceed limited?
As explained in the video each electrode is dipped in its ions solution (Zinc solfate and Cupric solfate respectively).
And yes we are interested in the initial direction of the reaction at Copper half-cell.
 
At first I concentrated on the part you listed, now I started from the beginning. Don't worry about this video, it is poorly thought and simplifies things beyond recognition.
 
ok, thus can you confirm that, at least initially, reaction proceed at the Copper half-cell such that copper cations in solution get reduced resulting in slightly positively charged Copper rod (assuming no external connection between electrodes)?
 
Last edited:
That's definitely what I expect would happen.

That is, assuming the idealized case in which rod - when immersed - had no initial charge.
 
I think it is unnecessary and not very helpful to invoke charge separations.
A Zn atom "wants to" transfer two of its electrons to Cu2+
It will do so if it is in contact, as seen this video

(and others, some more confusing).
And it will do so even if not in direct contact but via conductivity as in the galvanic cell, as long as there is a return pathway for electrons which is provided by the salt bridge.
 
Without charge separation there is no potential difference, so you can't ignore it without ignoring physics.
 

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