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KS3 (Years 7–9) · Chemistry

Acids and Alkalis

What is it

Students learn to use the pH scale and indicators to classify substances as acidic, neutral or alkaline, and understand neutralisation reactions between acids and alkalis, including simple examples like antacid tablets.

Why it matters

The pH scale and neutralisation reactions appear constantly in real life — from soil chemistry to digestion to industry — and are developed further with word and symbol equations at GCSE.

Exam tip

Memorise the pH scale direction (below 7 acidic, 7 neutral, above 7 alkaline) and at least one colour change for universal indicator — scale-reading questions are very common.

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