GCSEChemistryAQARevision NotesChemical AnalysisIdentification of Common GasesTest for Carbon Dioxide

Test for Carbon Dioxide (AQA GCSE Chemistry): Revision Note

Exam code: 8462

Written by: Stewart Hird

Reviewed by: Caroline Carroll

Updated on 2 July 2026

Test for carbon dioxide

The test for carbon dioxide involves bubbling the gas through an aqueous solution of calcium hydroxide (limewater)
If the gas is carbon dioxide, the limewater turns milky or cloudy

Test for carbon dioxide

Carbon dioxide turns limewater cloudy

Examiner Tips and Tricks

Sometimes students think that extinguishing a burning splint indicates carbon dioxide gas. However, while it is a property of carbon dioxide, other gases, such as nitrogen, will also do this, so the test is not definitive and should not be quoted in an exam answer.

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Author: Stewart Hird

Expertise: Chemistry Content Creator

Stewart has been an enthusiastic GCSE, IGCSE, A Level and IB teacher for more than 30 years in the UK as well as overseas, and has also been an examiner for IB and A Level. As a long-standing Head of Science, Stewart brings a wealth of experience to creating Topic Questions and revision materials for Save My Exams. Stewart specialises in Chemistry, but has also taught Physics and Environmental Systems and Societies.

Reviewer: Caroline Carroll

Expertise: Head of Content Delivery

Caroline graduated from the University of Nottingham with a degree in Chemistry and Molecular Physics. She spent several years working as an Industrial Chemist in the automotive industry before retraining to teach. Caroline has over 12 years of experience teaching GCSE and A-level chemistry and physics. She is passionate about delivering high-quality resources to help students achieve their full potential.