Limewater as Indicator of Carbon Dioxide Gas
Carbon dioxide gas from a cylinder is bubbled through limewater and calcium carbonate solid is formed causing the limewater to become cloudy. Catch carbon dioxide gas in a jar from a burning bunsen burner. Pour in fresh limewater and it will become cloudy indicating that there was in fact CO2 in that jar.
Methane when burned reacting with oxygen produces carbon dioxide gas (1).