What does a pH scale measure?

The pH scale is a numerical scale used to quantify the acidity or basicity (alkalinity) of a solution. It typically ranges from 0 to 14, where a pH of 7 is considered neutral, indicating a balanced concentration of hydrogen ions (H+) and hydroxide ions (OH-). Values lower than 7 indicate acidity, meaning there are more hydrogen ions present, while values higher than 7 indicate basicity, with a higher concentration of hydroxide ions.

Understanding the pH scale is crucial in various scientific fields, including chemistry, biology, and medicine, as it affects chemical reactions, biological processes, and the behavior of substances in solution. For example, in biological systems, maintaining a specific pH is vital for enzyme activity and overall homeostasis.

The other choices refer to different physical properties that do not pertain to the pH scale. Temperature measures heat levels in a solution, density refers to mass per unit volume, and conductivity relates to a solution's ability to conduct electricity, which is influenced by ion concentration but is not a direct measure of acidity or basicity.