A Level Chemistry OCR Practice Exam

In which type of reaction does a more reactive element displace a less reactive element from an aqueous solution of its ions?

1. Combination reaction

2. Displacement reaction

3. Decomposition reaction

4. Redox reaction

The correct answer is: Displacement reaction

The described reaction occurs when a more reactive element is able to replace a less reactive element in a compound, specifically when dealing with solutions of their ions. This process is typically classified as a displacement reaction. In displacement reactions, an element in a compound is replaced by another element that is more reactive. For example, if zinc is placed in a copper sulfate solution, zinc displaces copper to form zinc sulfate because zinc is more reactive than copper. While redox reactions involve the transfer of electrons and changes in oxidation states, not all displacement reactions are classified strictly as redox reactions, even though they can involve oxidation-reduction processes. Combination reactions involve the joining of two or more substances to form a single product, and decomposition reactions entail the breakdown of a compound into simpler products. Therefore, identifying it as a displacement reaction accurately captures the essence of the process.