Electrolysis - cleaning copper (1 Viewer)

[thunderdax]

Hey, I just found this written in my notes and I was fairly confused by it. Copper chloride is the main salt found when copper corrodes deep in the ocean. When copper is put as the cathode in an electrolytic cell, the following half equations happen:
Oxidation: 2Cl^----->Cl_{2 (g)}+2e^-

Reduction: CuCl^(s)+e^----->Cl^-+Cu^(s)

The problem is with the oxidation. Since the equation shown there has a higher reduction potential than the one for water, why doesn't water get oxidised instead?

 

[rama_v]

Both the Chloride ions and water will get oxidised, because their oxidation potentials are very close to each other. The reason behind this is that if there is a high enough voltage supplied, and if the concentration of chloride ions is high enough, then it too will be oxidised...

 

[Abtari]

im not too sure about this one...

are u sure those are the half equations for the electrolysis of copper chloride?

 

[sambo_rambo]

In the reduction reaction shown above, the Cl- is a spectator ion, so the real reduction equation would be Cu+ & e- --> Cu (solid) - sorry i'm shocking at writing equations on computers.