During electrodeposition, ions are separated from a solution by deposition on an electrode in an electrolytic cell. While reduction occurs at the cathode and oxidation occurs at the anode, deposition occurs on electrodes, such as platinum gauze electrodes, which have a large surface area. Metals, such as copper and nickel, with different reduction potentials, can be separated by electrodeposition. In an acidic medium, water undergoes oxidation at the anode, while copper is deposited at the cathode. The mass of plated copper is determined, and the electrode is cleaned. Then, the solution is made basic, and nickel is deposited on the same electrode. Electrodeposition can also separate ions such as copper two plus and lead two plus that deposit on different electrodes. Under acidic conditions, lead two plus ions undergo oxidation and deposit as lead dioxide on the anode. Meanwhile, copper two plus ions undergo reduction and deposit as copper metal on the cathode.