Question

(a) What happens when dilute hydrochloric acid is added to sodium carbonate? Write a balanced chemical equation of the reaction involved.
(b) Which gas is liberated when dilute hydrochloric acid reacts with sodium carbonate? How will you test for the presence of this gas?

Answer 1

(a) When sodium carbonate is treated with dilute hydrochloric acid, sodium chloride is formed and carbon dioxide gas is liberated.

Na₂CO₃(s) + 2HCl(aq) → 2NaCl(aq) + CO₂(g) + H₂O(l)

(b) Carbon dioxide gas is liberated when dilute hydrochloric acid reacts with sodium carbonate.
When the gas, liberated during the reaction, is passed through lime water, the lime water turns milky or a white precipitate of calcium carbonate is formed. This confirms that the gas is none other than carbon dioxide.