universal indicator

A universal indicator is a chemical solution used to determine the acidity or alkalinity of a substance. It changes color based on the pH level, which ranges from 0 to 14: acidic solutions (like lemon juice) have a pH below 7, neutral solutions (like water) are at pH 7, and alkaline solutions (like soap) have a pH above 7. This visual representation helps people easily identify how acidic or basic a solution is, making it a useful tool in laboratories, agriculture, and education for various practical applications.