Question

What is a litmus solution? How is it obtained?

Answer 1

Hint :An indicator is defined as a substance that changes its colour in acidic and basic medium. Litmus solution is used to determine whether a solution is acidic, basic or neutral, hence it is an indicator. We are aware that a litmus solution is obtained from a mixture of dyes.

Complete Step By Step Answer:
Litmus solution is a purple dye. The solution of Litmus is mainly extracted from lichens. The Litmus solution is used as an indicator to determine the acidic and basic nature of a solution.
Lichen plants belong to the class of Thallophyta. The litmus solution method involves the grinding and crushing of lichens.
A natural dye is extracted from lichens which is then dissolved in distilled water to obtain a litmus solution. Hence, it is used as an indicator to distinguish between acids and bases.
In acidic medium the colour of the solution turns red while in basic medium it turns to blue while in neutral solution there is no colour change.

Additional Information:
pH of a solution predicts the nature of a solution whether it is acidic, basic and neutral. Solutions having pH less than $7$ are acidic in nature, solutions having pH more than $7$ are basic in nature and solutions having pH $7$ are neutral in nature.

Note :
Indicators derived from natural sources are called natural indicators, Example: Lichen. Indicators prepared in the laboratory are called synthetic indicator examples: Phenolphthalein. Olfactory indicators are those that give different odour in acidic and basic solution, example: Onion.