Knowledge Organiser: Neutralisation
Key Terms
- Neutralisation: acid + base → salt + water
- Ionic equation: H⁺ + OH⁻ → H₂O
- Salt: ionic compound from acid-base reaction
- Base: reacts with acid to neutralise it
- Spectator ion: unchanged in reaction
Must-Know Facts
- Acid + Metal → Salt + H₂ (squeaky pop)
- Acid + Metal Oxide → Salt + Water
- Acid + Hydroxide → Salt + Water
- Acid + Carbonate → Salt + Water + CO₂
- Salt name: metal from base + acid ending
- HCl → chloride; H₂SO₄ → sulfate; HNO₃ → nitrate
Key Equations
- H⁺ + OH⁻ → H₂O (ionic equation for neutralisation)
- Mg + H₂SO₄ → MgSO₄ + H₂ (metal + acid)
- CuO + H₂SO₄ → CuSO₄ + H₂O (metal oxide + acid)
- Na₂CO₃ + 2HCl → 2NaCl + H₂O + CO₂ (carbonate + acid)
Common Mistakes
- Forgetting CO₂ in carbonate reactions: Acid + carbonate always produces three products — salt, water AND carbon dioxide
- Getting the salt name wrong: The first part comes from the metal/base, the second from the acid (HCl → chloride, H₂SO₄ → sulfate, HNO₃ → nitrate)
- Missing hydrogen gas from metal + acid: When a metal reacts with acid, hydrogen gas is produced — test with a burning splint (squeaky pop)
- Not writing the ionic equation correctly: The ionic equation for any neutralisation is always H⁺ + OH⁻ → H₂O — Na⁺ and Cl⁻ are spectator ions
Memory Aid
- Acid + Metal → Salt + H₂ (squeaky pop test)
- Acid + Metal Oxide → Salt + Water
- Acid + Metal Hydroxide → Salt + Water
- Acid + Metal Carbonate → Salt + Water + CO₂ (limewater test)