Displacement Reactions

This lesson covers displacement reactions as required by the Edexcel GCSE Combined Science specification (1SC0). You need to understand what displacement reactions are, predict when they will occur using the reactivity series, write word and symbol equations, and know about the thermit reaction.

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What Is a Displacement Reaction?

A displacement reaction occurs when a more reactive element takes the place of a less reactive element in a compound. The less reactive element is "displaced" — it is pushed out.

General Pattern

more reactive metal + compound of less reactive metal → compound of more reactive metal + less reactive metal

This only works if the free metal is higher in the reactivity series than the metal in the compound.

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Metal + Metal Salt Solution

The most common type of displacement reaction at GCSE involves placing a piece of metal into a solution containing a salt of a less reactive metal.

Example 1: Iron in Copper Sulfate Solution

iron + copper sulfate → iron sulfate + copper

Fe(s) + CuSO₄(aq) → FeSO₄(aq) + Cu(s)