When calcite (calcium carbonate, CaCO3) reacts with an acid, such as hydrochloric acid (HCl), it undergoes a chemical reaction known as an acid-base reaction. The reaction proceeds as follows:

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

In this reaction:

- CaCO3 represents solid calcite.

- 2HCl represents two molecules of hydrochloric acid in an aqueous solution (aq).

- CaCl2 represents calcium chloride, which is formed as a product of the reaction and remains dissolved in the solution.

- CO2 represents carbon dioxide gas, which is released as a product of the reaction and bubbles out of the solution.

- H2O represents water, which is also formed as a product of the reaction.

The reaction between calcite and hydrochloric acid is an example of an acid-base reaction because the acid (HCl) donates protons (H+) to the base (CaCO3), resulting in the formation of water (H2O) and a salt (CaCl2). The reaction continues until all the calcite has reacted or until all the acid has been consumed.