Question

What happens when carbon dioxide gas is passed through lime water for a considerable time?

Write the equation of the reaction involved.

Answer 1

If an excess of carbon dioxide gas is passed through lime water, the white precipitate first dissolves to form a soluble salt, calcium hydrogencarbonate, and the solution becomes clear again.

\[\ce{\underset{(Insoluble in water)}{\underset{(White ppt)}{\underset{Calcium carbonate}{CaCO3_{(s)}}}} + \underset{Carbon dioxide}{CO2_{(g)}} + \underset{Water}{H2O_{(l)}} -> \underset{(Soluble in water)}{\underset{Calcium hydrogencarbonate}{Ca(HCO3)2_{(aq)}}}}\]