Making 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
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.
- Carefully place the zinc into the conical flask.
- Collect 50 cm3 of hydrochloric acid in a small beaker.
- Connect the delivery tube and thistle funnel to the conical flask with the delivery tube in a basin of water.
- Have three gas jars/test tube filled with water also inverted in the basin of water.
- 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).
- Leave the gas jar/test tube inverted in the water to retain the gas.
- Repeat step 5 until three gas jars/test tubes of gas have been collected.
- 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