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I have just learnt about simple chemical cells but I have no idea how to determine which cells will work and which will not and the working principle of those cells.

I know that a chemical cell with $\ce{Zn}$ and $\ce{Cu}$ as electrodes and $\ce{CuSO4}$ as electrolyte will create a current in the external circuit. But why would $\ce{Zn}$ choose to lose electrons through the external circuit instead of having displacement reaction with the $\ce{CuSO4}$ electrolyte directly? And in the following cases, which of the cells will work and which will not?

    Electrodes   Electrolyte

1   Zn, Cu       ZnSO4

2   Zn, C        CuSO4

3   C, Cu        CuSO4

4   C, Cu        ZnSO4

And why do they (not) give out a current? Does it depend on the location of the elements in the electrochemical series? Does the choice of electrolyte affect the cells in any way?

Thank you.

Update

After reading several related questions, I find some contradictions between the answers. Is there a strict rule to decide which electrolyte to use or is it fine to use anything as long as it has good conductivity and does not react quickly with the electrodes?

Does it matter what electrolyte we use for a Galvanic Cell?

What is the Purpose of an Electrolyte in a Galvanic Cell?

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    $\begingroup$ Zn will react with CuSO4 directly all right, because it can. At the same time it would continue losing electrons via the external circuit, for the same reason. $\endgroup$ – Ivan Neretin Dec 29 '18 at 7:36
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in simple cells the oxidation,reduction reaction happens automatically so it depends on the location of the element in the electrochemical series ......the elements with a higher oxidation number in the top have more ability to lose electrons and and become a positive ion and this ability goes down when you go down the series ...... for ex. E°(oxidation of Zn ) > E°(oxidation of Cu) so the Zn loses 2e turning into Zn+2 ..... Cu+2 take these 2e and turn into cu ..... the electrolyte for sure affect the cell because it contains the ions of the cathode's element (Cu2+) that will be replaced by the onee from anode (Zn+2) as I mentioned before yet i'm not sure if that's what you want to know :)

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  • $\begingroup$ Thanks! But for cells that have Zn and C as electrodes, I believe that C cannot take the electrons from Zn. Then would the cell not give out a current or would the electrolyte take part in the redox reaction in some way? $\endgroup$ – YSL Dec 31 '18 at 7:48
  • $\begingroup$ well.. I think that zn will give the 2e directly to the cu2+ ions in the electrolyte so cooper will deposit on the Zn electrode it's like when you but a piece of Zn in the electrolyte CuSO4 and im not sure about the role of C that's why I didn't answer this part of you Question $\endgroup$ – Samah Dec 31 '18 at 8:06

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