Test for chlorine

你需要知道的

• Gases such as hydrogen, oxygen and carbon dioxide are all colourless, so a chemical test is needed to tell them apart.
• Chlorine is identified with damp litmus paper: it is bleached white (blue litmus may first turn red).
• The chlorine test sits alongside the other standard gas tests: a squeaky pop for hydrogen, a relit glowing splint for oxygen and milky limewater for carbon dioxide.
• Ammonia turns damp red litmus blue, so the colour change on litmus helps separate it from chlorine.

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