One cause of upset stomachs is excess stomach acid (HCI). Over-the- counter antacids contain various compounds such as sodium bicarbonate (NaHCO,), calcium carbonate (CaCO,), or magnesium carbonate (MgCO,) that react with acid to neutralize it. Write stoichiometrically balanced chemical equations for the reaction of these antacid compounds with HCl to produce a salt, CO,, and water. Which of these three com- pounds has the most acid neutralizing ability per gram?