What does pH paper indicate when tested in a liquid?

pH paper is a tool used to determine the acidity or alkalinity of a liquid solution. When pH paper is dipped into a liquid, it changes color based on the pH level of that liquid. The pH scale ranges from 0 to 14, where values below 7 indicate an acidic solution, values of 7 are neutral, and values above 7 indicate an alkaline (or basic) solution. This chemical property is crucial in various fields such as biochemistry, environmental science, and food science, as the pH of a solution can have significant implications on reactions, solubility, and biological activity.

Using pH paper allows for quick and easy assessment without the need for sophisticated instrumentation, making it an essential tool in laboratories and field studies. In contrast, other options relate to properties that pH paper cannot measure—such as boiling point, temperature, and density—which require different types of testing equipment or methods to assess accurately.