Chemical ChangesDiagram

The pH Scale

Part of Acids and Alkalis · GCSE GCSE Chemistry revision

This diagram covers The pH Scale within Acids and Alkalis for GCSE Chemistry. Revise Acids and Alkalis in Chemical Changes for GCSE Chemistry with 25 exam-style questions and 21 flashcards. This topic appears less often, but it can still be a useful differentiator on mixed-topic papers. It is section 3 of 12 in this topic. Focus on the labels, the relationships between parts, and the explanation that turns the diagram into an exam-ready answer.

Topic position

Section 3 of 12

Practice

25 questions

Recall

21 flashcards

📐 The pH Scale

pH scale from 0 to 14 showing colour gradient from red (strong acid) through green (neutral) to purple (strong alkali), with everyday examples at key pH values

Figure 1: The pH scale from strongly acidic (0) to strongly alkaline (14)

Keep building this topic

Read this section alongside the surrounding pages in Acids and Alkalis. That gives you the full topic sequence instead of a single isolated revision point.

Deep Dive: What Actually Makes an Acid?How It Works: H⁺ Ions Make Solutions Acidic, OH⁻ Make Them Alkaline The Chemistry of Lemons and Soap Higher Tier: Strong vs Weak Acids

Practice Questions for Acids and Alkalis

Which ion do acids produce when dissolved in water?

A. Hydroxide ions (OH⁻)
B. Oxide ions (O²⁻)
C. Hydrogen ions (H⁺)
D. Sodium ions (Na⁺)

1 markfoundation

Explain the difference between a strong acid and a concentrated acid.

2 marksstandard

Quick Recall Flashcards

Name two common alkalis

Sodium hydroxide (NaOH), Potassium hydroxide (KOH)

What is universal indicator?

An indicator that shows a range of colours across the pH scale (rainbow of colours from red to purple)

25 questions on Acids and Alkalis — practise free

Instant marking, adaptive difficulty, and 21 spaced repetition flashcards. Free until your GCSEs.

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Deep Dive: What Actually Makes an Acid?

How It Works: H⁺ Ions Make Solutions Acidic, OH⁻ Make Them Alkaline