Question

Explain the following:
(a) Bee stings are treated with ammonium hydroxide.
(b) When clothes stained with turmeric are washed with soap, they turn red.
(c) Acids or sour foods cannot be cooked in brass vessels.
(d) A medicine containing milk of magnesia and phenolphthalein is pinkish in colour.

Answer 1

(a) When a bee stings, it injects an acidic liquid in our body. This acidic liquid is treated by neutralising with ammonium hydroxide (base).

(b) Clothes stained with turmeric when washed with soap, which is basic in nature, turns turmeric to red.

(c) Acids or sour foods (contain acids) cannot be cooked in brass vessel because acid reacts with the copper metal in brass to displace hydrogen from acid and forms copper salt. This salt spoils the food and makes it poisonous to consume.

(d) Milk of magnesia (magnesium hydroxide) is a weak base. When it comes in contact with phenolphthalein, it turns its colour to pink. Thus, this medicine, which is used as an antacid (i.e., to neutralise excess hydrochloric acid in stomach) is pinkish in colour.