Answer:
Acid base indicators are weak and acids and bases, which are used to signify the end point of neutralization reaction. The type of indicator used for a neutralization reaction depends on the strength of the acid and the base, that are involved in the reaction. A good acid base indicator must have a good pH range and it must be able to produce specific and identifiable color in specific acid base medium.
or
Two good properties of an indicator are as follows-
1) It should be specific- It means that the changes, which are measured by the indicator should be expressed in precise terms so that appropriate assessment could be made.
2) It should be time bound- This means that the measurable changes should arrive withing a particular time limit.
Example of indicator- Litmus is an acid base indicator that turns acidic solutions red and basic solutions into blue color.
