LEARNATHON
III

Competition for grade 6 to 10 students! Learn, solve tests and earn prizes!

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Theory:

Do plants and animals have a \(pH\) sensitivity?

Our body works in a \(pH\) range of \(7.0\) to \(7.8\). Only a small range of \(pH\) change allows living organisms to live. The \(pH\) of different body fluids varies. For example, the \(pH\) of blood ranges from \(7.35\) to \(7.45\). Any deviation in this value leads to diseases. The ideal \(pH\) for blood is \(7.4\).
 
pH in our digestive system:
 
Our stomachs contain hydrochloric acid, which helps in food digestion, thus causing no harm to the stomach. The stomach produces too much acid during indigestion, causing pain and irritation. The \(pH\) of stomach fluid is about \(2.0\).
 
\(pH\) changes as the cause of tooth decay:
 
The \(pH\) of saliva is usually in the range of \(6.5\) to \(7.5\). Calcium phosphate, the hardest substance in our body, is the white enamel layer on our teeth. When the \(pH\) of the mouth saliva goes below \(5.5\), the enamel gets weathered. Toothpastes, which are usually basic, are used to clean the teeth and neutralise excess acid, preventing tooth decay.
 
pH of soil:

In agriculture, the \(pH\) of the soil plays an important role. For example, citrus fruits require slightly alkaline soil, while rice and sugarcane require acidic soil and neutral soil, respectively.
 
pH of rainwater:
 
The \(pH\) of rainwater is approximately \(7\), which means that it is neutral and represents its high purity. If the atmosphere is polluted with sulphur and nitrogen oxides, they get dissolved in rainwater and make the rainwater's \(pH\) less than \(7\). Acid rain is described as rainwater with a \(pH\) of less than \(7\). Acid rain decreases the \(pH\) of river water as it falls into them. In such rivers, aquatic life has a hard time living.