- The test for carbon dioxide involves bubbling the gas through an aqueous solution of calcium hydroxide (limewater)
- If the gas is carbon dioxide, the limewater turns milky or cloudy
Diagram showing the test for carbon dioxide gas
Sometimes students think that extinguishing a burning splint indicates carbon dioxide gas. However, while it is a property of carbon dioxide, other gases, such as nitrogen, will also do this, so the test is not definitive and should not be quoted in an exam answer.