Limewater: Limewater is a clear, colourless solution of calcium hydroxide in water having molecular formula .
When carbon dioxide is passed through limewater, the solution turns milky due to the formation of Calcium carbonate.
The balanced chemical reaction can be written as:
If you keep bubbling carbon dioxide through the limewater, an acid-base reaction occurs, causing the precipitate to dissolve and give soluble calcium hydrogen carbonate: