INTRODUCTION
- pH scale is a scale that is used to measure hydrogen ion concentration in a solution.
- The p in pH stands for ‘potenz’ in German, which means power.
- We can measure pH generally from 0(very acidic) to 14(very alkaline) on the pH scale.
- pH is simply a number that indicates the acidic or basic nature of a solution.
- The higher the hydronium ion concentration, the lower is the pH value.
- The pH of the neutral solution is 7.
- On the pH scale, a value less than 7 represents an acidic solution.
- As the pH value increases from 7 to 14, it represents an increase in OH- ion concentration in the solution, i.e., increase an increase in the strength of alkali.
- The strength of acids and bases depends on the number of H+ ions and OH- ions produced, respectively.
- Acids that give rise to more H+ ions are said to be strong acids, and acids that give rise to less H+ ions are said to be weak acids.
IMPORTANCE OF pH IN EVERYDAY LIFE –
Measuring of pH of a solution is very essential as its value should be known when dealing with biological and cosmetic applications.
ARE PLANTS AND ANIMALS pH SENSITIVE?
Our body works within the pH range of 7.0 to 7.8. When the pH of rainwater is less than 5.6 it is called acid rain. The pH of the river water lowers down when acid rain flows into the rivers. Then the survival of aquatic life forms becomes difficult.
pH OF THE SOIL –
For their healthy growth, plants require a specific pH range.
pH IN OUR DIGESTIVE SYSTEM –
Our stomach produces hydrochloric acid, which helps in the digestion of food without harming the stomach. The stomach produces too much acid, during indigestion, which leads to pain and irritation. People use bases called antacids, to get rid of this pain. The excess acid, is neutralise by these antacids. Magnesium hydroxide (milk of magnesia), a mild base, is commonly used for this purpose.
pH CHANGE AS THE CAUSE OF TOOTH DECAY –
When the pH of the mouth is lower than 5.5, tooth decay starts. Tooth enamel is made up of calcium phosphate which is the hardest substance in the body. When the pH in the mouth is below 5.5, it corrodes it. By degradation of sugar and food particles which are left over in the mouth after eating, bacteria present in the mouth produce acids. The best way to prevent this is to clean the mouth after eating food. Using toothpaste, which is generally basic, for cleaning the teeth can neutralize the excess acid and prevent tooth decay.
SELF DEFENCE BY ANIMALS AND PLANTS THROUGH CHEMICAL WARFARE –
An acid is being left by bee-sting which causes pain and irritation. On the stung area, use of a mild base like baking soda gives relief. Stinging hair of nettle leaves injects methanoic acid causing burning pain.
