# Working principle of simple chemical cells

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?

• 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. – Ivan Neretin Dec 29 '18 at 7:36