How to prepare carbon dioxide in the laboratory ?

Aim:

To prepare carbon dioxide in the laboratory.

Aids:

• Woulf’s bottle
• Gas jar with lid
• Marble chips
• Dilute hydrochloric acid

Method:

1. Put some marble chips in a Woulf’s bottle and fit the bottle with a thistle funnel and a delivery tube.

2. Place a collecting jar at the other end of the delivery tube.

3. Pour dilute hydrochloric acid in the bottle through the thistle funnel so that the marble chips are covered with the acid.

4. Collect the gas jars and cover them.

Observation:

Effervescence takes place in the bottle and the gas is collected by upward displacement of air.

Observe and test the properties of the gas formed. Some of them are as follows.

1. It is colourless.

2. It has a faint odour.

3. It dissolves in water immediately.

4. It is heavier than air.

5. If you put a lighted splinter in a jar containing carbon dioxide gas, it extinguishes. The gas does not support combustion.

6. If you put a wet blue litmus paper into the jar, it turns red. The gas is therefore acidic.

7. If add some limewater to the jar and shake, it turns milky.

8. If you put a burning magnesium ribbon in the jar, it burns with a dazzling light. This is because an oxide of magnesium is formed by reacting with carbon dioxide.

Precautions:

1. Check that the thistle funnel dips into the acid.

2. Do not leave the gas jars uncovered.