Identification of Common Gases

• Hydrogen Gas Colour


  Colourless
• Oxygen Gas Colour


  Colourless
• Carbon Dioxide Gas Colour


  Colourless
• Chlorine Gas Colour


  Greenish-yellow
• Sulfur Dioxide Gas Colour


  Colourless
• Ammonia Gas Colour


  Colourless
• Hydrogen Gas Smell


  Odourless
• Oxygen Gas Smell


  Odourless
• Carbon Dioxide Gas Smell


  Odourless
• Chlorine Gas Smell


  Pungent
• Sulfur Dioxide Gas Smell


  Suffocating
• Ammonia Gas Smell


  Pungent
• Hydrogen Gas Action On Litmus


  Neutral to litmus
• Oxygen Gas Action On Litmus


  Neutral to litmus
• Carbon Dioxide Gas Action On Litmus


  Moist blue to red
• Sulfur Dioxide Gas Action On Litmus


  Moist blue to red
• Hydrogen Gas Specific Test & Observation


  Lit splint at mouth of test tube extinguished with a 'pop' sound
• Oxygen Gas Specific Test & Observation


  Glowing splint inserted in test tube relights
• Oxygen Gas Specific Test Works Because...


  Oxygen gas supports combustion
• Carbon Dioxide Gas Specific Test & Observation


  White precipitate formed when bubbled through calcium hydroxide (limewater)
• Chlorine Gas Specific Test & Observation

  Moist blue litmus paper placed at mouth of test tube turns red, then bleaches
• Sulfur Dioxide Gas Specific Test & Observation


  Bubbling gas into aqueous acidified potassium manganate (VII) turns KMnO4 from purple to colourless
• Sulfur Dioxide Gas Specific Test Works Because...


  Sulfur Dioxide Gas is a reducing agent that reduces purple KMnO4 to colourless Mn 2+
• Ammonia Gas Specific Test & Observation


  gives a pale blue precipitate on passing through copper sulphate solution
• water vapour test


  turns blue cobalt chloride paper to pink