(a) Antacid tablets mainly consist of milk of magnesia or magnesium hydroxide, which neutralises the excess hydrochloric acid present in the stomach, thus reducing acidity. Hence, a person suffering from acidity takes antacid tablets.
(b) Liquid wastes from factories and industries contain acids, which when directly led into the water resources cause water pollution resulting in the death of fishes and other aquatic lives. So, to prevent this, factory wastes have to be treated with a base, like slaked lime, which neutralises the acidic effects.