GCSE Chemistry revision

Test for chlorine

Identification of common gases

AQA 4.8.2.4 Foundation & Higher

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Testing for Chlorine

Damp blue litmus paper is placed into a test tube containing the sample gas to test for chlorine.
If chlorine is present, the damp blue litmus paper turns white due to bleaching by the chlorine gas.
The paper may briefly turn red first, because chlorine dissolves in the water on the paper to form hydrochloric acid, which is acidic.
Chlorine is a poisonous gas, so this test must be carried out wearing a mask or inside a fume cupboard.

1. Testing for Chlorine AQA

Notes

Damp blue litmus paper is placed into a test tube containing the sample gas to test for chlorine.
If chlorine is present, the damp blue litmus paper turns white due to bleaching by the chlorine gas.
The paper may briefly turn red first, because chlorine dissolves in the water on the paper to form hydrochloric acid, which is acidic.
Chlorine is a poisonous gas, so this test must be carried out wearing a mask or inside a fume cupboard.