The correct answer is A because:

During the electrolysis of molten lead bromide, negative bromide ions are attracted to the positive anode
Here each bromide ion loses an electron:
- Br^– → Br + e^–
A bromine atom has an incomplete outer shell so will combine with another bromine atom to form a diatomic bromine molecule, Br₂:
- Br + Br → Br₂
Overall, to form one bromine molecule, 2 bromide ions each lose an electron, which is shown by the half equation:
- 2Br^– → Br₂+ 2e^–

B is incorrect as	it only shows the formation of one bromine atom
C is incorrect as	it shows the break down of bromine, not the formation
D is incorrect as	it is the bromide ions that lose electrons, so the - 2e^–would need to be on the other side: 2Br^–- 2e^–→ Br₂ this is now a correct half equation

Electrolysis (OCR Gateway GCSE Chemistry)

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