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What is the importance of the solution in an electrochemical cell?

  1. Sep 29, 2014 #1
    I'm wondering about the importance of the electrolytic solution in an electrochemical cell.
    For example, we have Zn/ZnSO4 and Cu/CuSO4.
    According to the electrochemical series, Zn will reduce Cu, and we will have a reaction.
    Zn(s) -> Zn2+(aq), Cu2+(aq) -> Cu(s).
    So there MUST be Cu2+ in the solution. But what about the electrode? If I had an Ag electrode in a copper solution, would the reaction proceed? (I am told it will not... but why?) The same net reaction would take place - Zn reducing Cu in solution, causing Cu to plate onto Ag. The only difference is that the electrode carrying electrons is now Ag.
    Similarly, if I had a Ag/AgNO3 solution and a Cu/Zn(NO3)2 solution, would Cu displace Ag in solution still? I mean, Cu oxidize to Cu2+ and enter solution even if there is Zn(NO3)2?
    Somewhat confused :P
    Help would be appreciated :)
  2. jcsd
  3. Sep 30, 2014 #2


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    Staff: Mentor

    Yes. Electrode can be inert in this case - besides, once few first copper atoms get reduced, you are back at a square one, copper electrode and copper in the solution.

    Yes, Zn2+ would be just a spectator.

    2Ag+ + Cu -> 2Ag + Cu2+
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