2. What method of gas collection is used during the preparation of carbon (II) oxide.

Over water because the gas is insoluble in water.

Downward delivery because the gas is 1 ½ times denser than air .

3. What is the purpose  of :

(i) Potassium/sodium hydroxide in Method 1

To absorb/ remove carbon (II) oxide produced during the reaction.

2KOH + CO₂ = K₂ CO₃ + H₂ O

(ii) Concentrated sulphuric(VI)acid in Method 2   Dehydrating agent –removes the element of water (Hydrogen and Oxygen in ratio 2:1) present in both        methanoic and ethan-1,2-dioic acid.

4. Describe the smell of carbon(II)oxide.

  Colourless and odourless.

5. State and explain the observation made when carbon(II)oxide is bubbled in lime water for a long time.

  No white precipitate is formed.

6. Dry and wet/moist/damp litmus papers were separately put in a gas jar containing dry carbon(II)oxide gas.

 State and explain the observations made.

Observation

  -blue dry litmus paper remains blue

  -red dry litmus paper remains red

  - wet/moist/damp blue litmus paper remains blue

  - wet/moist/damp red litmus paper remains red

Explanation

Carbon(II)oxide gas is a molecular compound that does not dissociate /ionize to release H+ ions and thus has no effect on litmus papers.

 Carbon(II)oxide gas is therefore a neutral gas.

State the observations made in flame K.

  Gas burns with a blue flame

Carbon(II)oxide is a reducing agent. Explain