A gas given off by a reaction is bubbled through limewater and the limewater turns milky. Which gas is it?

1. Limewater is an aqueous solution of calcium hydroxide. 2. Passing a gas through it is a standard test for one gas in particular. 3. If the solution becomes milky, the gas is carbon dioxide. 4. The milkiness comes from an insoluble solid forming in the liquid. 5. That solid is calcium carbonate, which does not dissolve and clouds the water. 6. Treating a dry salt with acid and getting this gas is a positive test for a carbonate. 7. Hydrogen is tested with a lit splint instead, so limewater would tell you nothing about it. _Source: Siyavula Physical Sciences Grade 10 (Everything Science, CC BY 4.0), Chapter 18: Reactions in aqueous solution_