6. Investigate the reaction of gasesMaking hydrogen gas

Apparatus and chemicals

• Conical flask with side arm, thistle funnel, delivery tube
• 3 gas jars/test tubes and 3 stoppers
• Basin/trough of water
• Test tube rack
• Basin/trough half-filled with water, bee hive shelf especially for gas jars
• Zinc approx. 2.5 g
• 50 cm³ of hydrochloric acid 1 mol/dm³
• Wooden splint

Method

The same method is used as for carbon dioxide except zinc (or sometimes magnesium ribbon) is used in place of calcium carbonate. Collect 3 gas jars/test tubes of hydrogen gas in the same way.

1. Carefully place the zinc into the conical flask.
2. Collect 50 cm³ of hydrochloric acid in a small beaker.
3. Connect the delivery tube and thistle funnel to the conical flask with the delivery tube in a basin of water.
4. Have three gas jars/test tube filled with water also inverted in the basin of water.
5. Carefully pour the hydrochloric acid into the thistle funnel, wait 5 s then carefully place the first water filled gas jar/test tube over the end of the delivery tube. Allow the gas jar/test tube to fill with gas (when all of the water has been displaced).
6. Leave the gas jar/test tube inverted in the water to retain the gas.
7. Repeat step 5 until three gas jars/test tubes of gas have been collected.
8. Remove each gas jar/test tube from the water as required for the following tests.

Testing the gas

To the first gas jar/test tube insert a lit splint – record your observations. You may need to repeat using a different gas jar/test tube of the gas