Question

When hydrochloric acid is added to a test tube containing sodium carbonate,a
gas is liberated immediately with brisk effervescence. Name the gas and describe

the test that confirms the identity of the gas. Give the related chemical equations.​

Answer 1

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

Na2CO3 (S) + 2HCl(aq) → 2NaCl(aq) + CO2 (g) + H2O(I)

CO2 gas is liberated during the reaction.When carbon dioxide gas formed in the form of brisk effervescence is passed through lime water, it turns the lime water milky. If excess of carbon dioxide gas is passed through the milky lime water, the solution becomes clear again. This confirms the presence of carbon dioxide gas