What happens to an indicator when carbon dioxide is bubbled through limewater?

When carbon dioxide is bubbled through limewater, which is a solution of calcium hydroxide, a chemical reaction takes place. The carbon dioxide reacts with the calcium hydroxide to form calcium carbonate, which is an insoluble compound. This reaction causes the limewater to become cloudy due to the formation of this white precipitate of calcium carbonate.

The process can be represented by the following chemical equation: [ \text{CO}_2 + \text{Ca(OH)}_2 \rightarrow \text{CaCO}_3 (s) + \text{H}_2\text{O} ]

The solubility of calcium carbonate is very low in water, leading to the observed cloudiness as it precipitates out of the solution. This key characteristic is what the indicator reflects when CO2 is introduced to limewater, making the correct answer that it goes cloudy.