Question

Why does lime water turns milky when we breathe into it?

Answer 1

Lime water turns milky when we breathe into it because we exhale carbon dioxide, which reacts with lime water to form calcium carbonate. Calcium carbonate is milky in appearance. The equation for the process is as follows.

$$\begin{gathered} \mathrm{Ca}(\mathrm{OH}{)}_2+\hspace{0.17em}{\mathrm{CO}}_2\to {\mathrm{CaCO}}_3+\hspace{0.17em}{\mathrm{H}}_2\mathrm{O} \\ \mathrm{Lime}\mathrm{Calcium} \\ \mathrm{water}\mathrm{carbonate}(\mathrm{milky}) \end{gathered}$$