Natural indicator among the following is

Question

Accepted Answer

Litmus is the correct answer as a natural indicator among the given options. Here's a detailed explanation supporting this choice:

1. **Litmus**: Litmus is a natural indicator derived from lichens, which are symbiotic associations between fungi and algae. It is one of the oldest and most commonly used natural indicators in chemistry. Litmus is used to determine the acidity or basicity of a solution. It turns red in acidic solutions and blue in basic solutions. Its natural origin and widespread use in educational and laboratory settings make it a quintessential example of a natural indicator.

2. **Phenolphthalein**: Phenolphthalein is a synthetic indicator, not a natural one. It is commonly used in titrations because it changes color in a pH range of about 8.2 to 10.0, turning from colorless in acidic solutions to pink in basic solutions. Its synthetic nature disqualifies it from being considered a natural indicator.

3. **Methyl orange**: Methyl orange is also a synthetic indicator. It is used in titrations involving strong acids and weak bases due to its clear color change from red in acidic solutions to yellow in neutral and basic solutions. Like phenolphthalein, its synthetic origin means it is not a natural indicator.

4. **Methyl red**: Methyl red is another synthetic indicator. It changes color from red in acidic solutions to yellow in basic solutions, typically used in titrations. Its synthetic production means it does not qualify as a natural indicator.

In conclusion, among the options provided, litmus is the only natural indicator, as it is derived from natural sources (lichens), whereas the other options are synthetic indicators. This justifies why Option 1, litmus, is the correct answer.