Testing for Four Carbon Gases: Chlorine, Oxygen, Hydrogen, and Carbon Dioxide

Chlorine Test

• Materials Needed: Test tube with sample gas, blue litmus paper.
• Procedure:
  • Dampen a piece of blue litmus paper.
  • Insert the damp blue litmus paper into the test tube containing the sample gas.
• Observations:
  • If chlorine is present, the blue litmus paper turns white.
  • The paper may briefly turn red due to the formation of hydrochloric acid before turning white.
• Safety Note: Chlorine is poisonous; use a mask or conduct the experiment in a fume cupboard.

Oxygen Test

• Materials Needed: Test tube with sample gas, glowing splint.
• Procedure:
  • Prepare a glowing splint (no flame, but glowing red at the end).
  • Place the glowing splint into the test tube with the sample gas.
• Observations:
  • If the gas is oxygen, the glowing splint will relight.

Hydrogen Test

• Materials Needed: Test tube with hydrogen, burning splint.
• Procedure:
  • Bring a burning splint close to the test tube containing hydrogen.
• Observations:
  • Hear a squeaky pop sound as hydrogen burns with oxygen to form water.

Carbon Dioxide Test

• Materials Needed: Test tube with gas sample, aqueous calcium hydroxide (lime water).
• Procedure:
  • Bubble the gas through the calcium hydroxide solution.
• Observations:
  • If carbon dioxide is present, the lime water turns cloudy.
  • Cloudiness is due to the formation of calcium carbonate, a solid.

Recap

• Chlorine: Turns damp blue litmus paper white.
• Oxygen: Relights a glowing splint.
• Hydrogen: Produces a squeaky pop with a lit splint.
• Carbon Dioxide: Turns lime water cloudy.

That's all for today's lesson on gas testing. See you next time!