Question

What is a natural and artificial indicator? Give some examples?

Answer 1

When we do an acid-base titration, then as soon as the color of the solution changes to light pink, we say that the reaction is complete. This is due to the addition of phenolphthalein added into the solution. Sometimes we use turmeric, grape juice, red cabbage, etc to find the substance is acidic or basic.

Complete answer:
If a substance changes its property when a specific compound is added, then the substance is known as indicators. In chemistry, we use many types of indicators, for finding the property of the substance, titrations, etc. So, there are two types of indicators, i.e., natural indicators and artificial (synthetic) indicators.
When we get an indicator from a natural substance like directly from plants and animals then they are known as a natural indicator. Some examples of natural indicators are turmeric, grape juice, red cabbage, litmus, etc.
Litmus is used to test the acid and base, the acidic substance changes the blue litmus to red, and the basic substance changes the red litmus to blue. When an acidic substance is added to red cabbage extract then it changes to pink and when a basic substance is added to red cabbage extract then it changes to green or yellow.
When we create an indicator in the laboratory using chemicals then it is known as a synthetic or artificial indicator. Some examples of synthetic indicators are phenolphthalein, methyl orange, methyl red, malachite green, etc.
These are used for finding the acid and bases as well as in titrations also.

Note:
The acids and bases contain hydrogen ions and hydroxyl ions respectively. The synthetic indicators change their color when they combine with these ions and after the neutralization the color changes.