Final answer:
A pH of 7 on the pH scale represents a neutral solution, such as pure water. The scale is logarithmic and ranges from ~0 to ~14, with values below 7 indicating acidity and above 7 indicating basicity. Each unit change reflects a tenfold change in hydrogen ion concentration.
Step-by-step explanation:
On the pH scale, the value 7 represents a neutral solution. This scale, which ranges from about 0 to approximately 14, helps determine the acidity or basicity of a solution. A substance with a pH value of 7 is neither acidic nor basic; it is neutral. The most common example of a neutral substance is pure water, which has a pH of 7.00. This implies that the concentration of hydrogen ions (H+) in the solution is at a level where it is neither donating nor accepting protons, resulting in a balanced state.
The pH scale is logarithmic, so a pH of 6 is ten times more acidic than a pH of 7, while a pH of 8 is ten times more basic. Thus, even small changes in pH can indicate significant changes in the concentration of hydrogen ions and the solution's overall acidity or basicity. Knowing the pH is crucial in various fields, including medicine, biology, and environmental science, as it affects chemical reactions, living organisms, and water quality.