How does an indicator function in a chemical reaction?

An indicator functions in a chemical reaction by changing color in response to acids or bases. This ability to change color allows for the visual detection of the pH level of a solution. When an indicator is added to a solution, it can indicate whether the solution is acidic or basic by altering its color at specific pH thresholds. For example, phenolphthalein is a common acid-base indicator that turns pink in basic solutions and remains colorless in acidic solutions.

This property is important in various applications, such as titrations in laboratory settings, where it helps to determine the endpoint of a reaction by signaling the transition between acidic and basic states. Indicators are crucial for monitoring chemical reactions because they provide immediate visual feedback about the chemical environment, which can guide further actions or adjustments in experiments.