Question

What happens when carbon dioxide passes through lime water?

Answer 1

Formation of Calcium carbonate $\left({\mathrm{CaCO}}_3\right)$:

• It is observed when carbon dioxide $\left({\mathrm{CO}}_2\right)$ gas is passed through lime water $\left(\mathrm{Ca}{\left(\mathrm{OH}\right)}_2\right)$.
• Calcium carbonate is responsible for the milkiness of the solution.
• When Carbon dioxide$\left({\mathrm{CO}}_2\right)$ passes through lime water$\left(\mathrm{Ca}{\left(\mathrm{OH}\right)}_2\right)$, it forms Calcium carbonate$\left({\mathrm{CaCO}}_3\right)$ and water.

Balanced chemical reaction equation:

$\underset{\mathrm{Carbon}\mathrm{dioxide}}{{\mathrm{CO}}_2\left(\mathrm{g}\right)}+\underset{\underset{(\mathrm{Calcium}\mathrm{hydroxide})}{\mathrm{Lime}\mathrm{water}}}{\mathrm{Ca}{\left(\mathrm{OH}\right)}_2\left(\mathrm{l}\right)}\to \underset{\mathrm{Milky}\mathrm{white}\mathrm{solution}}{{\mathrm{CaCO}}_3\left(\mathrm{s}\right)+{\mathrm{H}}_2\mathrm{O}\left(\mathrm{l}\right)}$

• Calcium carbonate$\left({\mathrm{CaCO}}_3\right)$ is milky in appearance.

Hence, the carbon dioxide turns lime water into a milky white solution.