any of the major appearances or aspects in which a thing of varying modes or conditions manifests itself to the eye or mind. 2. a stage in a process of change or development: Each phase of life brings its own joys. 3. a side, aspect, or point of view: This is only one phase of the question.
The pH of a neutral solution is 7. At this pH, the solution has equal concentrations of both the H+ and OH- ions, which is 10^-7 mole/litre. The presence of both the hydrogen and hydroxyl ions in equimolar concentrations makes the solution neutral.
The term pH refers to the concentration of hydrogen ions in water. Measured on a scale of 0 to 14, neutral water has a pH of 7, acids have a pH of less than 7, and bases have a pH greater than 7. While the desired pH for drinking water typically hovers around 7.0, the acceptable range for the pH of drinking water is between 6.5 and 8.5.