Explain why:
(a) An antacid tablet is taken when you suffer from acidity.
(b) Calamine solution is applied on the skin when an ant bites.
(c) Factory waste is neutralised before disposing it into the water bodies.

(a) We take an antacid such as milk of magnesia (base) to neutralize the excessive acid released in the stomach. Hence, it relieves us from acidity.

(b) Ant injects an acidic liquid (Formic acid) into the skin on biting which causes inflammation, to the skin. The effect of the acid can be neutralized by rubbing calamine solution as it contains zinc carbonate which is a very weak base and causes no harm to the skin.

(c) The wastes of factories contain acids. If acids are disposed off in the water body, the acids will harm aquatic life. So factory wastes are neutralized by adding basic substances.

Example: When sodium hydroxide(base) reacts with hydrochloric acid to form sodium chloride and water.

$NaOH(aq)  + HCl(aq) →NaCl(aq) + H_2O(l)$]