2 HCl (aq) + CaCO₃ (s) → CaCl₂ (aq) + H₂O (l) + CO₂ (g)
Here's what the equation represents:
* 2 HCl (aq): Two molecules of hydrochloric acid in an aqueous solution.
* CaCO₃ (s): One molecule of solid calcium carbonate.
* CaCl₂ (aq): One molecule of calcium chloride in an aqueous solution.
* H₂O (l): One molecule of liquid water.
* CO₂ (g): One molecule of gaseous carbon dioxide.
Explanation:
This reaction is a classic example of an acid-base reaction. The hydrochloric acid (HCl) is a strong acid, and calcium carbonate (CaCO₃) is a base. The reaction produces:
* Calcium chloride (CaCl₂): This is a salt that dissolves in water.
* Water (H₂O): This is formed by the reaction of the hydrogen ion (H⁺) from the acid and the hydroxide ion (OH⁻) from the base.
* Carbon dioxide (CO₂): This gas is released, causing the characteristic bubbling observed when an antacid tablet (which often contains calcium carbonate) is placed in water or stomach acid.
This reaction is the basis for how antacids work. Calcium carbonate neutralizes the excess stomach acid, providing relief from heartburn and indigestion.
