Brainlag PlusThe tests and positive results for hydrogen, oxygen, carbon dioxide and chlorine, and which reactions give which gas.
Four tests to know
- Hydrogen: hold a burning splint at the open end of the tube. It burns with a squeaky pop.
- Oxygen: put a glowing splint into the tube. It relights.
- Carbon dioxide: bubble it through limewater (calcium hydroxide solution). It turns milky: insoluble calcium carbonate forms.
- Chlorine: hold damp litmus paper in it. It is bleached white (blue litmus may go red first). Do it in a fume cupboard: chlorine is toxic.
Glowing splint for oxygen, burning splint for hydrogen: mixing these two up is the commonest slip.
The rest of this lesson and its 10 practice questions are in Plus.
Screen 1 of 3, free to read.
- 10 exam-style questions, marked as you go, each with a worked solution
- Anything you get wrong is saved to your flashcards