Preparing Carbon Dioxide in The Lab

This experiment aims to prepare carbon dioxide gas and study its physical and chemical properties.

The apparatus and chemicals required for this experiment are: 

Apparatus

• Woulfe’s bottle
• Gas jar
• Thistle funnel
• Delivery tube
• Single bored corks: 2
• Trough
• Splinter

Materials

• Marble chips
• Dilute hydrochloric acid
• Red and blue litmus paper
• Limewater
• Mg ribbon

Procedure

The procedure followed for this experiment is as follows: 

1. Take a few small pieces of marble chips in Woulfe’s bottle. Seal both the mouths of the bottle with single bored corks.
2. Insert a thistle funnel into the bottle through one of the corks 
3. Insert the delivery tube into the bottle through the other cork. Place the other end of the delivery tube in the glass jar.
4. Add, dropwise, 10 mL of dil. Hydrochloric acid to the Woulfe’s bottle through the thistle funnel
5. Collect the liberated gas in a gas jar and record the colour of the gas
6. Bring an ignited splinter and introduce it into the gas jar. Record your observations
7. Insert a moist or wet red litmus paper in the gas-filled jar and record the colour change 
8. Invert the gas jar filled with the gas over a trough of water. Record your observations
9. Now, pass the liberated gas through freshly prepared limewater in a test tube. Record the colour change in the test tube.

Thus, it can be concluded that: 

• Carbon dioxide (CO₂) gas is produced when metal carbonate reacts with dilute HCl.

• CO₂ gas turns limewater milky due to the formation of a white precipitate of CaCO_3.

• CO₂ is a colourless and odourless gas.

• It is a non-supporter of combustion.

• CO₂ is acidic in nature as it turns blue litmus red, but red litmus remains unchanged.

• CO₂ dissolves in water to produce carbonic acid.

H₂O(l) + CO₂(g) → H₂CO₃(aq)

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