Question

Why does the lime water turn milky when carbon dioxide is passed through it? Explain using chemical reactions.

Answer 1

Lime water turns milky because carbon dioxide reacts with calcium hydroxide to form a clear white insoluble precipitate of calcium carbonate (CaCO₃).

Chemical Reaction:

\[ \text{Ca(OH)}_2\text{ (aq)} + \text{CO}_2\text{ (g)} \longrightarrow \text{CaCO}_3\downarrow \text{ (white ppt.)} + \text{H}_2\text{O (l)} \]