Mention 5 gases that can be collected by downward displacement of air and upward displacement of air

Here are 5 gases that can be collected by each method:

• Downward displacement of air (for gases denser than air):

  1. Carbon dioxide (CO₂)
  2. Chlorine (Cl₂)
  3. Sulfur dioxide (SO₂)
  4. Hydrogen chloride (HCl)
  5. Nitrogen dioxide (NO₂)

• Upward displacement of air (for gases less dense than air):

  1. Hydrogen (H₂)
  2. Ammonia (NH₃)
  3. Methane (CH₄)
  4. Helium (He)
  5. Nitrogen (N₂)