Chemical ChangesDiagram

The pH Scale

Part of Acids and Alkalis — GCSE Chemistry

This diagram covers The pH Scale within Acids and Alkalis for GCSE Chemistry. Revise Acids and Alkalis in Chemical Changes for GCSE Chemistry with 20 exam-style questions and 20 flashcards. This is a high-frequency topic, so it is worth revising until the explanation feels precise and repeatable. 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

20 questions

Recall

20 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)

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Deep Dive: What Actually Makes an Acid?

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