What does the pH scale measure?

The pH scale is specifically designed to measure the acidity or alkalinity of a solution. It is a logarithmic scale that typically ranges from 0 to 14, with 7 being neutral. A pH value below 7 indicates acidity, which means the solution has a higher concentration of hydrogen ions (H+). Conversely, a pH value above 7 indicates alkalinity, where the concentration of hydroxide ions (OH-) is higher. This measurement is crucial in many scientific fields, including chemistry, biology, and environmental science, as it influences chemical reactions, biological processes, and the health of ecosystems. The pH scale does not relate to temperature, purity, or pressure, which are measured by different scales and instruments, making the focus on acidity the correct aspect of this question.