What happens when an acid reacts with a metal hydrogen carbonate? Write equation of the reaction which takes place.

When an acid is added to metal hydrogen carbonate, carbon dioxide gas is liberated with a metal salt and water.

Eg: When sodium hydrogen carbonate reacts with hydrochloric acid, sodium chloride and water is formed with an evolution of carbon dioxide gas

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