# Chlorine water is added separately to two test tubes, one containing potassium bromide solution and another containing potassium iodide solution. State what is observed in each test tube and explain why these reactions occur.

> Pearson Edexcel International GCSE Chemistry (4CH1) — 2.2 Group 7 (halogens) · State and Explain · 4 marks

> Chlorine is a halogen in Group 7 of the periodic table. It can react with solutions of other halide salts.

## Mark scheme (4 marks)

1. Chlorine displaces bromine from potassium bromide solution, so the solution turns orange/brown
2. Chlorine displaces iodine from potassium iodide solution, so the solution turns brown/dark brown
3. Chlorine is more reactive than both bromine and iodine, so it can displace them from their compounds
4. Down Group 7, halogens become less reactive because the atoms have more electron shells, making it harder to gain an electron

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