What best defines a displacement reaction?

• A. A reaction where a metal dissolves in water.
• B. A reaction where a compound breaks into simpler substances.
• C. A reaction where a more reactive element replaces a less reactive element in a compound.
• D. A reaction where two elements form a single product.

Answer: (C)

Displacement reactions occur when a more reactive element pushes a less reactive element out of a compound. The more reactive element donates electrons to the compound’s ions, causing the less reactive element to be released and a new compound to form. A classic example is zinc metal reacting with copper sulfate: Zn + CuSO4 → ZnSO4 + Cu, where zinc displaces copper from its compound because zinc is more reactive.

This is why the correct description matches the idea that a more reactive element replaces a less reactive element in a compound. The other scenarios describe different reaction types: dissolving a metal in water isn’t about swapping elements, decomposition breaks a compound into simpler substances, and synthesis forms a single product from elements.