Question

what is an indicator? name three common indicators

Answer 1

Indicators dissociate slightly in a solution producing ions and dissociated molecules. The colour of the ions is dependent on the hydrogen ion concentration. The three common indicators are: 1.Litmus paper. 2.Methyl orange.

Answer 2

Indicators are weak inorganic compounds which change color in accordance with the pH of the solution. 
A few common indicators used in the laboratory are: 
1. Litmus Paper 
2. Methyl Orange 
3. Universal Indicators