[lokifenrir96]

Hi, I don't really understand how in a simple cell where there are 2 electrodes immersed in a shared electrolyte, it is a closed circuit.

Take for example a simple cell where Zinc is the anode, and Iron is the cathode. Let the electrolyte be copper (II) sulfate.

Electrons flow from Zinc to Iron, hence Zn2+ ions are produced at the anode and flow into the electrolyte. Cu2+ ions migrate from the electrolyte towards the cathode, where they are reduced to Cu. However, I'm under the impression that for the circuit to be 'closed', the electrons must complete a full circuit (which doesn't really make sense in this context), though I don't see how the movement of charged ions will complete the circuit. Please enlighten me!

On a side note, can someone please tell me under what circumstances NO3- is reduced to NO and NO2, and under what circumstances it is reduced to NH3? Thanks...

[Borek]

To close a circuit you need a way to transfer charge, it doesn't necessarily mean transfer of electrons.

[stymar]

You can put the iron piece in the copper sulfate without the zinc anode and the copper will still plate out onto the iron.