It‘s about electrolysis. There‘s something about electroplating with copper that I don‘t quite understand. If I were to electroplate a key with Cu, I would place it at the negative electrode and I would place a copper bar at the +ve electrode right? And the electrolyte is a solution of CuSO4 (I mean, a solution. The salt is not molten, but dissolved in water). So, the Cu ions that leave the bar plus the ions in the solution are supposed to go to the key. But as hydrogen from the water is higher in the reactivity series, shouldn‘t hydrogen ions, instead of Cu ions, go to the key?? Then, electroplating with Cu is impossible in a solution, isn‘t it?? Am I right? I‘ve got to revise this over the summer, because next September I‘ll be in Y11 and I‘ll have a science test the week we come back from holidays. HEELP!! A million stars and points for the best explanation ;)
Remember the concentration of H+ ion in pure water is only 1 x 10^-7 M! The CuSO4 solution used for plating is typically 1% or higher, about 0.1 M.