Electrodes in a CuSO4 electrolysis

[NiCKEL]

In the classic example that the 2016 curriculum gives is an electrolytic cell with CuSO4 solution and inert or copper electrodes. It explains that with copper electrodes, a slighlty different reaction takes place at the anode and there is no net reaction, but a reaction is still occurring. Since both the inert and copper electrode examples say they result in the formation of copper on the cathode, I assume that's all from Cu2+ from the solution? So it doesn't actually matter what the anode is if the goal is to cover the object?

 

The reason I ask this is becuase I've seen questions like "in ordere to plate an X with Y, the X needs to be the...(multiple choice)" and I was wondering if one of the rules is would be: the solution needs to contain what you want to coat the item with. Originally, we wrote notes on the anode must be X and the cathode is what's being coated, but with the above example it seems to say it's more dependent on the solution than the anode, is that right?

[Msj Chem]

If the anode and cathode are both made of copper, then you will get oxidation at the anode and reduction at the cathode. The anode will lose mass as it is oxidised and the cathode will gain mass as Cu²⁺ ions are reduced. The colour of the CuSO₄ solution (blue) remains constant. 

If you were to use a graphite anode in CuSO₄ solution, then whatever material the cathode is made of would become coated in copper as the Cu²⁺ ions are reduced. The colour of the CuSO₄ solution will get paler until it is colorless. At this point, no more copper would be deposited at the cathode (because all the Cu²⁺ ions have been reduced). How much metal would be plated depends on the concentration of the solution. 

To electroplate an object, you use an anode made of the same metal to be coated at the cathode in a solution of its ions. 

https://youtu.be/w6iAO_ldIPg

Edited December 2, 2015 by Msj Chem

[NiCKEL]

Ok so I was wondering if the anode was not the metal to be plated, but the solution had some of the ions (e.g. Ag⁺) would the cathode get plated a tiny bit? Because there's still SOMEthing available right, and the cathode is still undergoing reduction anyways?

Maybe this is extremely impractical and a solution alone would never contain enough ions to "plate" an item but just theorectically speaking...

[Msj Chem]

Yes, if the solution contains Ag⁺ ions, then they would be reduced and silver would be plated on whatever metal was at the cathode. 

But as you say, it would be impractical to plate something like this.