(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 ?

(a) When dilute hydrochloric acid reacts with sodium carbonate then sodium chloride, carbon dioxide, and water are formed.

$N{a}_{2}C{O}_3+2HCl⟶2NaCl+H_{2}O+C{O}_2$

(b) When dilute hydrochloric acid reacts with sodium hydrogen carbonate, Carbon dioxide gas is liberated. We recognize the presence of carbon dioxide by passing it through lime water which turns milky or a white precipitate of calcium carbonate is formed. This confirms that the gas is carbon dioxide.