Which pH value indicates a neutral solution?

A pH value of 7 indicates a neutral solution. This understanding is based on the pH scale, which ranges from 0 to 14, with values lower than 7 representing acidity and values higher than 7 representing alkalinity. Pure water, at 25 degrees Celsius, has a pH of 7. This value reflects an equal concentration of hydrogen ions (H⁺) and hydroxide ions (OH⁻), signifying that the solution is neither acidic nor basic.

In this context, a pH below 7 (like 0 or 4) indicates an acidic solution, where there are more hydrogen ions than hydroxide ions. Conversely, a pH above 7 (like 14) indicates a basic (or alkaline) solution, where there are more hydroxide ions than hydrogen ions. Understanding the pH scale and its implications is fundamental in chemistry and is crucial for applications in fields like medicine and biology.