Hydrogen, oxygen and carbon dioxide
Hydrogen is a colourless, odourless gas.
Test for hydrogen
A lit splint applied to hydrogen gas will result in a popping sound.
This is because the hydrogen is flammable and burns in oxygen once lit.
\(\text{hydrogen + oxygen}\rightarrow{water}\)
2H2 + O2 \(\rightarrow\) 2H2O
Oxygen
Oxygen is a colourless, odourless gas.
Test for oxygen
A glowing splint applied to a sample of oxygen gas will relight.
Carbon dioxide
Carbon dioxide is a colourless, odourless gas.
Test for carbon dioxide
When carbon dioxide is bubbled through limewater (calcium hydroxide solution) the limewater changes from colourless to milky.
The limewater test for carbon dioxide