10 minutes maximum! Can you do it in 5?

Q1-4 Select the correct gas. Which of the following gases ...

1. relights a glowing splint?
2. turns limewater milky?
3. bleaches damp blue litmus paper white?
4. ignites with a pop when a burning splint is applied?

Several tests for gases are:

  • A.   turn limewater milky
  • B.   relights a glowing splint
  • C.   gives a squeaky pop with a lit splint
  • D.   bleaches damp universal indicator paper

Select the correct test for the gas which is produced ...

5. ...during the complete combustion of a fuel.
6. ...when zinc reacts with hydrochloric acid.
7. ...during the catalytic decomposition of hydrogen peroxide.
8. ...when sodium metal reacts with water.
9. ...during the electrolysis of molten zinc chloride.


10. An unknown compound was added to acid and produced a gas which turned limewater milky. The compound could be ...

  • A.   sodium chloride
  • B.   potassium sulfate
  • C.   magnesium nitrate
  • D.  calcium carbonate