1. Acid + Metal → Salt + Hydrogen
Mg + 2HCl → MgCl₂ + H₂
Fizzing/bubbles seen. Test: squeaky pop with lit splint.
2. Acid + Metal Oxide → Salt + Water
CuO + H₂SO₄ → CuSO₄ + H₂O
Black copper oxide dissolves to give blue solution.
3. Acid + Metal Hydroxide → Salt + Water
HCl + NaOH → NaCl + H₂O
Classic neutralisation — often no visible change.
4. Acid + Metal Carbonate → Salt + Water + CO₂
CaCO₃ + 2HCl → CaCl₂ + H₂O + CO₂
Fizzing/effervescence. Test CO₂: turns limewater cloudy.
This how it works covers The Four Types of Acid Reactions within Neutralisation Reactions for GCSE Chemistry. Revise Neutralisation Reactions in Chemical Changes for GCSE Chemistry with 20 exam-style questions and 20 flashcards. This topic appears regularly enough that it should still be part of a steady revision cycle. It is section 5 of 13 in this topic. Use this how it works to connect the idea to the wider topic before moving on to questions and flashcards.
Practice questions for Neutralisation Reactions
Which word equation correctly represents a neutralisation reaction?
Explain why the ionic equation for any strong acid-alkali neutralisation is always H⁺(aq) + OH⁻(aq) → H₂O(l).