When metal carbonates react with acids, carbon dioxide gas, water, and a salt are produced. The general equation is:
Metal carbonate + Acid → Salt + Water + Carbon dioxide
For example, when calcium carbonate reacts with hydrochloric acid, calcium chloride, water, and carbon dioxide are formed:
CaCO₃(s) + 2HCl(aq) → CaCl₂(aq) + H₂O(l) + CO₂(g)
Similarly, metal hydrogencarbonates react similarly, producing carbon dioxide, water, and a salt. The reaction of sodium hydrogencarbonate with hydrochloric acid yields sodium chloride, water, and carbon dioxide:
NaHCO₃(s) + HCl(aq) → NaCl(aq) + H₂O(l) + CO₂(g)