Chemistry study notes
Theories of Acids and Bases
Choose the definition that explains the reaction: aqueous ions, proton transfer or electron-pair donation.
A-Level 9476 (2026-2027)
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3 topicsArrhenius: what changes in water?
Identify acids and bases by the ions they produce in aqueous solution.
Bronsted-Lowry: follow the proton
Find donors, acceptors and conjugate pairs, including amphiprotic species.
Lewis: follow an electron pair
Explain acid-base reactions without requiring water or proton transfer.
Scope
Learning outcomes
4. Theories of Acids and Bases. Use the outcome map to find the explanation for a particular syllabus requirement.
See the learning outcome map
4(a) Understand and apply the Arrhenius theory.
- Acids and hydrogen ions in water
- Bases and hydroxide ions in water
- Aqueous scope and neutralisation
4(b) Understand and apply proton-transfer theory.
- Bronsted-Lowry donors and acceptors
- Conjugate acids and bases
- One-proton/one-charge distinction and amphiprotic examples
4(c) Understand and apply the Lewis theory.
- Electron-pair donors and acceptors
- Non-aqueous systems
- Named BF3 and NH3 reaction