Topic: Indicators

Indicators are weak acids or bases that change color based on the solution's pH. The color change happens because the indicator exists in an equilibrium between two forms, each having a different color. The goal is to choose an indicator whose transition range closely matches the equivalence point pH of the titration. For example, phenolphthalein is ideal for weak acid-strong base titrations (equivalence point pH > 7), while methyl orange is better for strong acid-weak base titrations (equivalence point pH < 7).