GCSEScienceAQACombined Science: TrilogyChemistryRevision NotesChemical AnalysisIdentification of Common GasesTest for Chlorine

Test for Chlorine (AQA GCSE Combined Science: Trilogy): Revision Note

Exam code: 8464

Stewart Hird

Last updated

AQA Combined Science: Trilogy: ChemistryAQA Chemistry

Test for chlorine gas

  • The test for chlorine gas makes use of litmus paper

  • If chlorine gas is present, damp blue litmus paper will turn red and then be bleached white

  • It turns red initially as acids are produced when chlorine comes into contact with water

  • Chlorine also has a characteristic sharp, choking smell 

  • Chlorine should always be handled in a fume cupboard due to its toxicity

Test for chlorine gas

Test for Chlorine gas showing damp red litmus paper bleaching white

Chlorine bleaches damp blue litmus paper white

Examiner Tips and Tricks

You should distinguish between properties of gases and tests for gases. Chlorine 'smells like swimming pools' is a characteristic, but not an acceptable means of identification. 

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Stewart Hird

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.

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