Acid-base indicators are commonly used to determine the pH of a solution. They undergo a noticeable color change in response to changes in acidity or basicity, providing a visible indication of the solution’s pH. This makes indicators valuable tools in laboratories and various industries for qualitative assessment of acidic, neutral, or alkaline conditions. They are used in titrations, educational experiments, and quality control processes. Common indicators include litmus paper, phenolphthalein, bromothymol blue, and methyl orange. Their ability to visually signal pH changes facilitates the identification of acids or bases and aids in the monitoring of chemical reactions.