(a) Acidity is caused when an excess of acids is produced in the stomach.
The antacid tablet contains base-like milk of magnesia which neutralizes
the acid produced in the stomach, thus giving relief. Hence, it is used while suffering from acidity.
(b) When an ant bites, it injects formic acid into the skin. Calamine solution
contains zinc carbonate which is basic in nature. Therefore, it is applied on the
skin to neutralize the effect of formic acid to bring relief for the affected person.
Hence calamine neutralizes the effect of formic acid.
(c) Factory wastes contain acids. Therefore, these wastes, when thrown
directly to water bodies, harm aquatic lives. Hence, these wastes are
neutralized with basic chemicals before disposing to water bodies.