What is the primary function of an indicator in titration?

The primary function of an indicator in titration is to determine the end-point of the reaction. Indicators are substances that change color at a specific pH range, allowing the experimenter to visually identify when the titration has reached its endpoint. This endpoint is the point at which the amount of titrant added is stoichiometrically equivalent to the amount of substance in the sample solution. The color change signifies that the reaction has reached the desired point, thus facilitating accurate measurement of the concentration of the analyte.

While changing the color of the solution is a characteristic of indicators, that function alone does not encompass their role in the context of titration. Enhancing the reaction speed or maintaining the pH of the solution are not primary functions associated with indicators. Their main purpose is specifically about signaling the endpoint through a visible color change coinciding with the completion of the reaction.