To make calcium chloride, you need hydrochloric acid (HCl). The chemical reaction between calcium carbonate (CaCO3) and hydrochloric acid (HCl) produces calcium chloride (CaCl2), water (H2O), and carbon dioxide (CO2).

The balanced chemical equation for this reaction is:

CaCO3(s) + 2HCl(aq) → CaCl2(aq) + H2O(l) + CO2(g)