JAMB Chemistry 2023 Paper

Concept:An antacid must be a basic compound that can neutralise excess hydrochloric acid in the stomach.Explanation:Antacids are mild bases used to neutralise excess stomach acid ($\mathrm{HCl}$).True antacids include magnesium hydroxide, aluminium hydroxide, calcium carbonate, and sodium bicarbonate.These compounds react with $\mathrm{HCl}$ to form harmless salts and water.The chlorides listed in the options are neutral or acidic salts, not bases.For instance, $\mathrm{MgCl_2}$ and $\mathrm{AlCl_3}$ hydrolyse in water to give acidic solutions, which would worsen heartburn.$\mathrm{NaCl}$ and $\mathrm{CaCl_2}$ do not neutralise stomach acid.Therefore, none of the listed options is a salt used as an antacid.Answer:None of the given options is the salt found in antacid medications for relieving heartburn and indigestion.