Chapter 22.3, Problem 14R

To determine

To Identify: The purpose of an indicator in a titration circuit.

Explanation of Solution

Introduction:The process of completely reacting a solution of known concentration with a solution of unknown concentration is known as titration.

The process of titration is used to determine the unknown concentration of the other solution.

The solution of known concentration is termed asstandard solution.

An indicator is a substance which when added to the solution of unknown concentration, undergoes some noticeable change thereby indicating the end point or equivalent point of titration.The end point or equivalence point indicates that the solution is neutralized.

The indicator possess one colour in the presence of the solution whose concentration is to be estimated and another colour when the standard solution completely neutralises the other solution, indicating the end point.

As the standard solution is added to the solution of unknown concentration drop by drop the indicator shows change of colour. The colour change at the end point is clear and sharp.

Conclusion:The indicator in a titration experiment indicates the end point of the titration by showing a significant change in colour.