Which Electrode Builds Up Metal Precipitate in a Galvanic Cell?

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Discussion Overview

The discussion revolves around the identification of the electrode in a galvanic cell that builds up a metal precipitate, focusing on the roles of the cathode and anode in the context of reduction and electron flow. The scope includes conceptual understanding and clarification of electrochemical processes.

Discussion Character

  • Homework-related
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • One participant states that the cathode is where reduction occurs, suggesting that it is rich in electrons, which allows metal cations to be reduced to metal.
  • Another participant questions whether a positively charged cathode could attract cations, asserting that the cathode does not contain metal cations as they are reduced upon contact.
  • A participant expresses a common misconception that the cathode is a metal plate containing metal cations, seeking clarification on the nature of the cathode and its role in attracting cations from the solution.
  • It is noted that both electrodes function as conductors surrounded by ions, with reactions occurring only at the surface where the phase boundary exists.

Areas of Agreement / Disagreement

Participants express differing views on the charge of the cathode and its ability to attract cations, indicating a lack of consensus on the nature of the cathode and its role in the galvanic cell.

Contextual Notes

There are unresolved assumptions regarding the charge of the cathode and the presence of metal cations, as well as the specifics of the electrochemical processes occurring at the electrodes.

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Homework Statement



In a galvanic cell, the electrode that builds up a precipitate of metal (known as plating out) is:
A. the cathode, and its surface is rich in positive charge.
B. the anode, and its surface is rich in positive charge.
C. the cathode, and its surface is rich in electrons.
D. the anode, and its surface is rich in electrons.

Homework Equations


----N/A----

The Attempt at a Solution



I guess my dilemma revolves around the solution that the book gave. The book: "Answer C. The cathode is defined as the electrode at which reduction occurs. This eliminates choices B and D. Metal cations are converted into metal at the cathode. For a cation to be converted into a metal, it must gain electrons (undergo reduction), so the surface of the cathode must be rich in electrons."

I understand that reduction and metal plating occurs at the cathode, my problem is the second part of the answer. Wouldn't the cathode be rich in positive charge? My understanding is that the cathode contains the metal cations, which will eventually pick up the electrons coming from the anode. I can also understand that the cathode would gather electrons on its surface so that metal cations can pick them up. However, I'm more inclined to pick A than C. Please help! Thanks in advance.
 
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Would be positively charged cathode able to attract cations?

Cathode doesn't contain metal cations, they get reduced the moment they touch the surface.

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methods
 
Borek said:
Would be positively charged cathode able to attract cations?

Cathode doesn't contain metal cations, they get reduced the moment they touch the surface.

Oh, so are the metal cations usually in solution? I was always under the assumption that the cathode was a metal plate containing the metal cations. At least that's what it looks like every time I see a simple diagram of a galvanic cell.

So is the cathode electrode just a conductor allowing electrons to gather on its surface, which attracts metal cations from the cathode solution allowing reduction to occur?

Thanks for your response! :smile:
 
Both electrodes are just conductors, surrounded by ions. Reaction takes place only at the surface (phase boundary).

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Awesome! Answered all my questions. Thanks again, Borek!
 

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