I have a solution of copper(II) ions and several cations. I am trying to reduce the copper ions to copper metal with electricity. My Ideas was to use silver as the anode and a copper wire as the cathode. I have seen people say to do this using platinum as the anode, however this is expensive. I was wondering if silver could be used as an alternative anode because it has a higher reduction potential than copper. If not, could any metals besides gold and platinum work. I have attached a picture of my proposed cell. I have tried the cell, but the silver began to corrode and form a silvery deposit, probably a silver salt.
1 Answer
In principle, electrically depositing copper(II) ions onto a silver electrode should be possible. As it should also be possible to deposit those ions on just about every other cathode in existence as long as there are no more noble cations in solution.
However, depending on what you want to do with the copper, you may run into problems. Do you want copper-plated silver? That should be fine. Do you want to redissolve the copper to get a pure solution by acidifying? In that case, you cannot use the typical $\ce{HNO3}$ method because that would oxidise the silver, too, and you would end up with a mixture of copper(II) and silver(I) nitrates in solution.
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1$\begingroup$ No, I am trying to get the copper as a powder by reducing it with a copper cathode and silver anode. I started with copper ore, dissolved it in acid, and I am now trying to bring it to the metallic state. I wanted to make sure that the silver would not oxidize or corrode. $\endgroup$ Jun 6, 2016 at 0:39
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$\begingroup$ @popgalop You won’t get copper as a powder, you will get a metallic plating on your cathode. $\endgroup$– JanJun 6, 2016 at 0:41
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2$\begingroup$ Or maybe $\ce{Ag}$ would dissolve to some extent, and that would be a problem. Normally people use copper anode for this purpose, so as not to bother about impurities. Copper in, copper out. $\endgroup$ Jun 6, 2016 at 4:47
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2$\begingroup$ Otherwise, use carbon (graphite). It will oxidize, but who cares. It won't reduce anyway. $\endgroup$ Jun 6, 2016 at 5:22
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1$\begingroup$ Then put the carbon electrode in another vessel and join them by a salt bridge. $\endgroup$ Jun 9, 2016 at 18:16