acid-base indicators

Acid-base indicators are substances that change color depending on the pH level of a solution. They help identify whether a solution is acidic (sour), neutral, or basic (alkaline). For example, litmus paper turns red in acids and blue in bases. Indicators are useful in chemical tests, medicine, and environmental analysis to determine the acidity or alkalinity of a sample quickly. The color change occurs because the indicator molecules react differently with hydrogen ions (H⁺) at various pH levels, providing a visual cue about the solution’s properties.