Chemical AnalysisDiagram

The Five Key Gas Tests

Part of Gas TestsGCSE Chemistry

This diagram covers The Five Key Gas Tests within Gas Tests for GCSE Chemistry. Revise Gas Tests in Chemical Analysis for GCSE Chemistry with 20 exam-style questions and 15 flashcards. This is a high-frequency topic, so it is worth revising until the explanation feels precise and repeatable. It is section 3 of 13 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 13

Practice

20 questions

Recall

15 flashcards

Four panels showing gas tests: hydrogen with lit splint giving squeaky pop, oxygen with glowing splint relighting, carbon dioxide turning limewater milky, and chlorine bleaching damp litmus paper

Figure 1: The four key gas tests for GCSE Chemistry — learn the test, result, and equation for each.

The Five Key Gas Tests

  • Hydrogen (H₂): Burning splint test — "squeaky pop"
  • Oxygen (O₂): Glowing splint test — relights the splint
  • Carbon dioxide (CO₂): Limewater test — turns milky/cloudy
  • Chlorine (Cl₂): Damp blue litmus paper — bleaches to white
  • Ammonia (NH₃): Damp red litmus — turns blue; or white fumes with HCl rod

Keep building this topic

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

Practice Questions for Gas Tests

Which observation confirms a gas is hydrogen when tested with a burning splint?

  • A. A squeaky pop is heard
  • B. The splint relights
  • C. Limewater turns milky
  • D. Damp litmus paper bleaches white
1 markfoundation

Explain why hydrogen gas produces a squeaky pop when tested with a burning splint.

2 marksstandard

Quick Recall Flashcards

Test for oxygen gas (O₂)?
Use a glowing splint (blow out flame first). POSITIVE RESULT: Glowing splint relights/bursts into flame (O₂ supports combustion)
Test for hydrogen gas (H₂)?
Use a burning splint. POSITIVE RESULT: 'Squeaky pop' sound (H₂ burns rapidly: 2H₂ + O₂ → 2H₂O)

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