Electrolysis and electroplating

Learning objectives

Define electrolysis as the decomposition of an ionic compound, when molten or in aqueous solution, by the passage of an electric current, and identify the anode (positive electrode), cathode (negative electrode) and electrolyte in a cell

Identify the products at each electrode and describe the observations made during the electrolysis of molten lead(II) bromide, concentrated aqueous sodium chloride and dilute sulfuric acid using inert platinum or carbon electrodes

State that metals or hydrogen are formed at the cathode and non-metals other than hydrogen at the anode, and predict the products of electrolysing a binary compound in the molten state

Describe the transfer of charge during electrolysis (electrons moving in the external circuit, electron loss at the anode and gain at the cathode, ions moving in the electrolyte) and construct ionic half-equations for the reactions at each electrode (Extended)

Predict the products of electrolysing a halide compound in dilute or concentrated aqueous solution, and describe the electrolysis of aqueous copper(II) sulfate with inert carbon electrodes and with copper electrodes, including its use to purify copper (Extended)

State that metal objects are electroplated to improve their appearance and resistance to corrosion, and describe how an object is electroplated, e.g. with copper using a copper anode, the object as the cathode and aqueous copper(II) sulfate as the electrolyte