Acids, Bases & Protons (Edexcel IGCSE Chemistry)

Exam board Pearson Edexcel · IGCSEUpdated 2024-08-21

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Spec point — understand acids and bases in terms of proton transfer understand that an acid is a proton donor and a base is a proton acceptor

The earlier definition of an acid and a base can be extended
In terms of proton transfer, we can further define each substance in how they interact with protons

Acids are proton donors as they ionize in solution producing protons, H⁺ ions
These H⁺ ions make the aqueous solution acidic
Example: hydrochloric acid

HCl (aq) → H⁺(aq) + Cl^–(aq)

Bases (alkalis) are proton acceptors as they ionize in solution producing OH^- ions which can accept protons
These OH^- ions make the aqueous solution alkaline
Example: sodium hydroxide

NaOH (s) → Na⁺(aq) + OH^–(aq)

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