acids, bases and salts — Science STD 10 — Question
Gujarat BoardEnglish MediumSTD 10Scienceacids, bases and salts4 Marks
Question
Explain importance of pH in everyday life.
✓
Answer
Explanation of the importance of $pH$ in everyday life are as follows:
$(1)$ Importance of $pH$ in existence of living beings:
The physiological reactions occurring in human body take place in the $pH$ range of $7.0$ to $7.8$.
If the value of $pH$ changes, the survival of living organisms becomes difficult and biological reactions get disturbed.
Generally, the $pH$ value of (pure) water is $7.0$, while the $pH$ of rain water is $5.6$.
When $pH$ of rain water becomes less than $5.6$, it is called acid rain.
When the acid rain flows into water reservoirs such as rivers, ponds, then $pH$ of the water decreases; so, the survival of aquatic life kingdom like fish, micro-organisms and aquatic vegetation are being risked.
$(2)$ Importance of $pH$ in soil:
Plants require a specific $pH$ range for their healthy growth.
The soil whose $pH$ is between $6.5$ to $7.3$, the growth and development of shrubs is good.
The farmers add lime $(CaO)$ to the acidic soil to neutralise it, while to neutralise basic soil, they add gypsum $(CaSO_4.2H_2O)$ to the soil.
$(3)$ Importance of $pH$ in digestive system:
We know that the digestion of food takes place in stomach.
Our stomach produces hydrochloric acid.
It helps in the digestion of food without harming the stomach; but during indigestion, sometimes the stomach produces excess acid which causes pain and irritation, which we commonly call as acidity.
Basic substances are taken as a remedy of the acidity, which are known as antacids; which neutralise the excess acid.
Mostly, mild basic substances such as baking soda $(NaHCO_3)$ and milk of magnesia $(Mg(OH)_2)$ are used as antacids.
$(4)$ Importance of $pH$ in stopping decay of teeth:
When the pH of the inner side of the mouth is less than $5.5$, the decay of teeth starts.
The outer layer of teeth is made-up of hard substance enamel like calcium phosphate $(Ca_3(PO_4)_2).$
It does not dissolve in water, but gets corroded when pH of inner side of mouth becomes less than $5.5$.
Acid is produced by decomposition of particles of food and saccharides (sugar) by bacteria inside the mouth after taking food; which is responsible for decay of teeth.
Hence, good habit of cleaning mouth should be followed after eating.
The toothpastes which are used for teeth cleaning possess basic nature.
They neutralise the acid produced inside the mouth and prevent tooth decay.
$(5)$ In the remedy of bite of honey-bee:
When we are stung by honeybee then sting of bee releases formic acid due to which we experience pain and irritation.
To get the relief in the effect of bee-sting basic substances such as an aqueous solution of baking soda is applied around the place of bite which neutralises the acidic poison.
Moreover, stinging hair of nettle leaves inject methanoic acid which causes the effect of burning pain.
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