Test for Gases

• Carbon Dioxide CO2

  • colourless and odourless
  • bubble gas through limewater, if CO2 present, white precipitate is formed
• Hydrogen H2


  • colourless and odourless
  • place a burning splint near the mouth of the test tube, if hydrogen is present, burning splint is extinguished with a pop sound
• Oxygen O2


  • colourless and odourless
  • place a glowing splint near the mouth of the test tube, if oxygen is present, the glowing splint relights
• Ammonia NH3


  • colourless and pungent
  • place a piece of damp red litmus paper near the mouth of the test tube, if ammonia is present, damp red litmus paper turns blue
• Sulfur dioxide SO2


  • colourless and pungent
  • place a piece of filter paper soaked in acidified potassium manganate (VII) near the mouth of the test tube, if sulfur dioxide is present, purple acidified potassium manganate (VII) turns colourless
• Chlorine Cl2


  • yellow green and pungent
  • place a piece of damp blue litmus paper near the mouth of the test tube, if chlorine is present, damp blue litmus paper turns red and becomes bleached