Universal Indicator - GCSE Chemistry Definition

A universal indicator is a special solution used in chemistry to find out if a substance is an acid or an alkali and how strong it is. It changes colour when added to a substance, showing a different colour depending on the pH level of that substance. The pH scale ranges from 0 to 14, where 0 to 6 means the substance is acidic, 7 means it is neutral, and 8 to 14 means it is alkaline. For example, if the universal indicator turns red, the substance is strongly acidic, while if it turns dark purple, the substance is strongly alkaline. This makes the universal indicator a useful tool for quickly and easily finding out whether a solution is acidic or basic in an experiment.