C3.4

Electrolysis is the process by which an electric current is passed through a compound causing a chemical change.

An electrolyte - A compound in its liquid state or in solution which contains mobile ions and conducts electricity Two electrodes - which conduct electricity to the electrolyte Electrical supply such as a power pack or battery

Cathode where positive ions go as it’s negatively charged Anode where negative ions go to as it’s positively charged

The ions have become discharged.

When an ion becomes discharged the ions in the electrolyte replace them by diffusion and convection.

Inert electrodes are electrodes that aren’t changed during electrolysis usually made from un reactive materials such as copper or platinum.

Hydrogen is produced at the cathode unless an ion from a less reactive metal is present. Oxygen is produced at the anode unless ions from an element in group 7 are present.

Electroplating uses non-inert electrodes.

The cathode is the object that you want to coat The anode is a piece of the metal you want to coat the object with.

The electrolyte contains the ions of the metal you want to coat with.

During electroplating metal ions are discharged on the surface of the cathode. These ions are replaced by ions leaving the anode. Metal leaves the anode and is deposited on the cathode until it’s used up.

Both electrodes made from the material you want to purify. Cathode purified anode is impure. Cathode gains the pure ions from anode and at the anode it decreases in mass and the impurities and collect under it.