 We've placed one molar copper sulfate into the U-tube. We've placed copper electrodes into each half of the U-tube. We're going to pass current through the system. You can see that gas has not evolved at either electrode, so we're not oxidizing or reducing the water. Reducing the copper ion requires less voltage than reducing the water, so we'll see copper metal plate out on the electrode. On the anode side is difficult to oxidize a sulfate ion. The copper metal electrode, however, can be oxidized, and so we'll oxidize the copper to copper ion. The copper ion will go into solution. If we look at the cathode, we can see that we have a bright surface, which is the result of having copper metal plate onto the surface of the electrode. If we look at the anode, we can see that it also has changed appearance at the tip. It's a little shinier because we've lost copper metal from the surface. The copper metal has been oxidized to copper ion.