Answer:When acids react with carbonates,---CO2--------gas is liberated.
Step-by-step explanation:
Acids liberate Carbon IV oxide when they react with Carbonates bicarbonate
For examples
Acid +carbonate ⟶ Salt + Water + Carbon dioxide
Calcium carbonate + Hydrochloric acid will give Calcium chloride with the liberation of CO2 gas and water
CaCO3 + 2HCl →CaCl2 + CO2 + H2O
To Test for the presence of the CO2 Liberated, we pass the gas through lime water, if the lime water turns milky, then C02 gas is confirmed.