The common measure of the acidity of a solution is known as pH. The pH scale ranges from 0 to 14 and quantifies the concentration of hydrogen ions (H+) in a solution. A pH of 7 is considered neutral, while values below 7 indicate acidity, and values above 7 indicate alkalinity. Monitoring pH is essential in various fields, including chemistry, biology, environmental science, and medicine, as it affects chemical reactions, biological processes, and the health of ecosystems.