Question

1. State and explain the factors that are considered when collecting a gas by displacement of:
   1. air
   2. Water
2. Other than collecting a gas by displacement of air or water, state another method that can be used to collect a gas.

Answer 1

1.  
   1. Air
      • Density of the gas 
      • If the gas is lighter than air - upward delivery or downward displacement of air 
        OR
      • If the gas is denser than air-downward delivery.
   2. Water
      • Solubility in water
      • If the gas is insoluble or slightly soluble in water.
2.  
   1. Gas syringe
   2. Solidification-SO₂
   3. Condensation
   4. Freezing
   5. Collection over mercury
   6. Liquidification