Acid Base & Salt - Class 10th Science
Importance of pH in Everyday Life
Are plants and animals pH sensitive?
All plants and animals are sensitive towards pH. Living organism works within the narrow range of pH. Our body also works within the narrow range of pH of 7.0 to 7.8 only. If this pH range increases or decreases, living organism find it difficult to survive.
We have to face the problem of acidity if pH value of our stomach decreases, i.e. becomes more acidic. If the pH value of our mouth decreases, our tooth starts decaying. If the pH value of soil decreases or increases than normal, soil becomes infertile. If the pH value of river water decreases, fish starts dying. Hence, it is clear that living organisms are sensitive towards the value of pH.
pH of soil for healthy growth of plants
Plants grow properly and gives proper yield if the soil is neither acidic nor basic i.e. neutral. This means pH of the soil should be equal to 7 for healthy growth of plants.
Often wrong harvesting and use of excess fertilizers increase or decrease the pH of soil from normal. This affects the growth of plants which is resulted in lower yield.
If pH value of soil is found lower than 7, i.e. soil becomes acidic; soil is treated with calcium oxide, calcium hydroxide or chalk. After treatment excess acid present in soil neutralizes and soil becomes fertile again.
Similarly, often pH value of soil becomes greater than 7, i.e. becomes basic. In such condition also soil is treated with neutral manure or compost or pyrite or gypsum which neutralizes the basic nature of soil.
Government gives the facility to farmers to get their soil checked at regular basis.
pH in our digestive system
Walls of our stomach produce hydrochloric acid which kills germs present in food if any. This hydrochloric acid also helps in the digestion of food we eat.
Digestion takes place in our stomach in acidic medium. The pH value of our stomach is near 1.2. But in the case of overeating the receptors of walls of stomach get wrong message and start producing more acid. This decreases the pH value of our stomach, resulting in the condition of hyperacidity. This creates problems and we feel burning sensation and uneasiness, and sometimes vomiting tendency also.
To neutralize excess acid produced by stomach, an antacid a medicine is taken orally. This neutralizes the extra acid produced by our stomach and we feel comfortable. Milk of magnesia is taken as medicine which is a mild base.
pH change as the cause of tooth decay
Normal pH value of our mouth is about 6. This is because of saliva produced by glands present in our mouth. This means that medium of our mouth is slightly acidic.
Tooth’s enamel is made of calcium phosphate. This is insoluble in water but start corroding because of acid. Some times food particles get trapped between teeth gap. After some time bacteria present in mouth start acting upon carbohydrate, which is a type of sugar, present in food items and produced acid. This acid decreases the pH value of mouth from 6. This acid starts decaying the enamel of tooth. After degradation of enamel teeth becomes sensitive and bad breadth starts coming out of the mouth. If decaying of tooth is not stopped timely, it is resulting in tooth loss.
The action of bacteria can be prevented by brushing of teeth using toothpaste. Toothpaste is basic in nature and it neutralizes the more acid produced in mouth because of bacteria.
Self defense by animal and plants through chemical warfare:
All living organism got self defense tools as a gift from nature. For example deer, buffalo, cows, etc. has long and sharp horn, lizard can change its colour, bee has sting, etc.
Defense weapon of bee:
Honey bees are armed with chemical sting as defense tool. Honey bee contains acid in their sting. When a person is stung by honey bee, honey bee injects acid and pushes and leaves its sting in skin. Because of acid present in sting, victim feels pain near the stung area. Area of stung get swollen after some time.
Honey bee sting contains methonic acid, so rubbing of baking soda, toothpaste or other mild base at the stung area neutralizes the effect of acid and gives relief to the victim from pain.
Defense weapon of ant:
Ant has bite as their defense tool. Ant bite also contains methanoic acid similar to honey bee. Thus, by rubbing of mild base near the ant bite gives relief to the victim. However, there are some type of ant found in world whose bite is very dangerous and immediately hospitalization is required in such case.
Plants with defense weapon:
Some plants are armed with sting as defense tool, such as nettle. Plants of nettle has sting. A person who touches the nettle leaves gets stung similar to honey bee. Nettle leaves also contain methanoic acid, which resulting in pain and irritation near the stung area. In such case also rubbing of mild base, such as slaked lime, baking powder, etc. gives relief to the victim from pain.