Saloni took a piece of burning charcoal and collected the gas evolved in a test tube.
(a) How will she find the nature of the gas?
(b) Write down the word equations of all the reactions taking place in this process.

Litmus is a natural indicator. A natural Indicator is a type of indicator that can be found naturally and can help us to know whether the material tested is an acidic substance or a basic substance. It is obtained from lichens. The process of obtaining a litmus solution needs the crushing and grinding of lichens.

Some examples of natural indicators other than litmus are:  red cabbage, turmeric, turnip skin, curry powder, etc.

It is used to test materials for acidity and basicity. This solution can also be used to differentiate between acids and bases. When acid is added to a litmus solution, it changes to red. When a base is added, it changes to blue. Neutral litmus paper is purple in colour.