Indicators are the substances which change different colours when come in contact with Acids & bases. There are two types of indicators:-natural and artificial. Rose petals,litmus and turmeric are natural indicators while phenolphthalein is a artificial indicator.

Explanation:

Natural indicators are substances that can be found in nature and can be used to determine the acidity or alkalinity of a solution. They change color depending on the pH of the solution they are added to. Some examples of natural indicators include litmus, turmeric, and rose petals.

Phenolphthalein is not a natural indicator. It is a synthetic organic compound that is commonly used as an acid-base indicator. Phenolphthalein is colorless in acidic solutions and turns pink or red in alkaline solutions. It is not naturally occurring and is typically synthesized in a laboratory.

Why is phenolphthalein not a natural indicator?
Phenolphthalein is not naturally occurring because it is a synthetic compound that is chemically synthesized. It cannot be found in nature in its pure form. Natural indicators, on the other hand, are substances that can be found in plants, fruits, and flowers. They are often extracted from these natural sources and used as indicators.

Examples of natural indicators
1. Litmus: Litmus is a natural indicator derived from lichens. It turns red in acidic solutions and blue in alkaline solutions.
2. Turmeric: Turmeric is a spice that contains a natural indicator called curcumin. It turns yellow in acidic solutions and red in alkaline solutions.
3. Rose petals: Rose petals can also be used as a natural indicator. They turn pink in acidic solutions and green in alkaline solutions.

Conclusion:
Phenolphthalein is not a natural indicator because it is a synthetic compound that is chemically synthesized. It cannot be found in nature in its pure form. Natural indicators, on the other hand, are substances that can be found in plants, fruits, and flowers.