ChemistryCode 5070
Electrolysis
What this topic asks you to be able to do
- Define electrolysis as a process in which an electric current brings about decomposition of an ionic compound that is molten or present in aqueous solution
- Identify, in a simple electrolytic cell: (a) the positive electrode, called the anode (b) the negative electrode, called the cathode (c) the molten or aqueous substance being electrolysed, called the electrolyte
- Describe how charge is transferred during electrolysis, covering: (a) electrons moving through the external circuit (b) electrons being lost or gained at the electrodes (c) ions moving through the electrolyte
- identify what is produced at each electrode and describe what is seen when electrolysing: (a) molten lead(II) bromide (b) concentrated aqueous sodium chloride (c) dilute sulfuric acid, with inert platinum or carbon/graphite electrodes
- Identify what is produced at each electrode, and describe what is seen, when aqueous copper(II) sulfate is electrolysed with inert carbon/graphite electrodes and also with copper electrodes
- state that the cathode produces metals or hydrogen, whereas the anode produces non-metals other than hydrogen
- Predict, at each electrode, the identity of the products when a binary compound is electrolysed while molten
- Predict which products form at each electrode when a halide compound is electrolysed as a dilute or a concentrated aqueous solution
- Construct ionic half-equations that describe the reaction at the cathode, to show reduction, and the reaction at the anode, to show oxidation
- state that metal items are electroplated in order to make them look better and resist corrosion
- Describe the procedure by which metals undergo electroplating