Halogen - Displacement Reactions
Chemistry: Edexcel IGCSE, topic 8.1.7
Displacement Reactions - Halogens
More reactive substances can displace (replace) less reactive substances from compounds. For example, chlorine can displace bromine from a compound:
Displacement reaction
- Sodium bromide + chlorine → sodium chloride + bromine.
- 2NaBr + Cl2 → 2NaCl + Br2
Bromide ions (Br-)
- Bromide ions are oxidised (electrons are lost):
- 2Br- → Br2 +2e-.
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Chlorine (Cl2)
- Chlorine is reduced (electrons are gained):
- Cl2 + 2e- → 2Cl-.
Spectator ions
- The sodium ions do not change in the reaction, so we call them spectator ions.
Test yourself on Halogen - Displacement Reactions
More reactive substances can displace less reactive substances from compounds. Chlorine can displace bromine from sodium bromide. What does this show about the reactivity of chlorine compared with bromine?