(i) An antacid tablet is taken when you suffer from acidity. To neutralize acidity, antacid tablet such as milk of magnesia is taken because it contains Magnesium hydroxide (base) which neutralizes the effect of acids.
(ii) Calamine solution is applied on skin when an ant bites. Ant bite contains formic acid which gets neutralized by calamine solution (zinc carbonate).
(iii) Factory waste is neutralized before disposing it into the water bodies. Factory waste usually contains acids, so they have to be neutralized as they can kill aquatic animals and plants. Some basic substances are used to neutralize such wastes.
