In a fume cupboard molten lead (ll) bromide is electrolyzed using graphite electrodes.

Question

Write half equations for the reactions at cathode and anode

Answer 1

During the electrolysis of molten lead(II) bromide (PbBr₂) using graphite electrodes, the following half-equations occur at the cathode and anode:

1. Cathode Reaction: At the cathode, lead ions (Pb²⁺) gain electrons (reduction) to form lead metal (Pb): \[ \text{Pb}^{2+} + 2e^- \rightarrow \text{Pb} (s) \]

2. Anode Reaction: At the anode, bromide ions (Br⁻) lose electrons (oxidation) to form bromine gas (Br₂): \[ 2\text{Br}^- \rightarrow \text{Br}_2 (g) + 2e^- \]

Overall, the electrolysis of molten lead(II) bromide results in the deposition of lead at the cathode and the generation of bromine gas at the anode.