Acids, Bases and Salts — Science STD 7 — Question

The neutralisation reactions play a very important role in our everyday life.
Some of the examples that involves neutralisation reaction are as follows
Indigestion
Our stomach produces Hydrochloric Acid (HCl) which helps in digesting the food present in it. Sometimes, excess of hydrochloric acid causes indigestion. It can lead to pain and irritation in the stomach.
To relieve indigestion, we take an antacid which contains bases, e.g. milk of magnesia has magnesium hydroxide. It neutralises the excess acid present in the stomach and cures indigestion.
Ant Bite
When an ant bites, it injects an acidic liquid into the skin of the person which causes burning sensation. The sting of an ant contains an acid called formic acid.
The effect of the acid can be neutralised by rubbing a mild base, e.g. baking soda solution (sodium hydrogen carbonate) or calamine solution which contains zinc carbonate.
Thus, being a base, baking soda solution or calamine solution neutralises the acidic liquid injected by the ant and cancel its effect.
Soil Treatment
The soil may be acidic or basic naturally. The plants do not grow well, if the soil at a place is too acidic or too basic.
Excessive use of chemical fertilisers makes the soil acidic. When the soil is too acidic, it is treated with bases like quicklime (calcium oxide) or slaked lime (calcium hydroxide). These bases neutralise the excess acid present in the soil and reduce its acidic nature.
If the soil is basic, organic matter called manure or compost is added to it. The organic matter releases acids which neutralises the basic nature of the soil.