What is the role of indicators in classifying solutions?

• A. They change the temperature of the solution.
• B. They provide color evidence to classify solutions as acidic, neutral, or basic.
• C. They determine the exact concentration of a solution.
• D. They convert the solution to a different substance.

Answer: (B)

Indicators are substances that change color depending on how acidic or basic a solution is. This color change gives a quick, visual clue about the level of hydrogen ions in the solution, letting you classify it as acidic, neutral, or basic. For example, litmus paper turns red in acidic solutions and blue in basic ones, while universal indicators show a range of colors corresponding to pH values. This helps you judge the solution’s identity without measuring exact numbers.

They don’t change the temperature of the solution, they don’t tell you the exact concentration, and they don’t convert the solution into something else. Their role is to provide a color signal that indicates the pH category.