Electrolysis science experiment

www.fizik.si Copper (II) sulphate solution can be electrolysed using inert steel electrodes. During electrolysis, the cathode is coated with a layer of reddish-brown solid copper. The blue colour of the solution fades gradually as more copper is deposited. The resulting electrolyte also becomes increasingly acidic. An aqueous solution of copper (II) sulphate contains four types of ions: Ions from copper (II) sulphate: Cu2+ and SO42- Ions from water: H+ and OH- At the anode: OH- ions and SO42- ions are attracted to the anode. OH- ions give up electrons more readily than SO42- ions. Consequently, OH- ions are preferentially discharged to give oxygen gas. 4OH- (aq) à 2H2O (l) + O2 (g) + 4e- The SO42 ions remain in solution. At the cathode: H+ ions and Cu2+ ions are attracted to the cathode. Copper is lower than hydrogen in the reactivity series. Cu2+ ions accept electrons more readily than H+ ions. As a result, Cu2+ ions are preferentially discharged as copper metal (atoms). Cu2+ (aq) + 2e- à Cu (s) The H+ ions remain in solution.