The Halogen - Displacement 1
Chemistry: Cambridge International GCSE Supplement, topic 8.3.3
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 The Halogen - Displacement 1
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?