Here's why:
* Reaction: When carbon dioxide (CO₂) dissolves in water (H₂O), it forms carbonic acid (H₂CO₃).
* Carbonic Acid & Calcium Hydroxide: Carbonic acid reacts with calcium hydroxide to form calcium carbonate (CaCO₃) and water.
* Calcium Carbonate: Calcium carbonate is a white, insoluble solid, which is what causes the cloudy appearance.
The chemical equation for this reaction is:
Ca(OH)₂ (aq) + CO₂ (g) → CaCO₃ (s) + H₂O (l)
This reaction is often used as a simple test for the presence of carbon dioxide.
