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.
When the pH is 7 ([H+] = 10-7 mol/liter): Number of hydrogen ions precisely equals the number of hydroxide ions (OHâ) And the solution is neutral - Neither acidic or basic. Pure water has a neutral pH of 7, or 10-7 mol/liter (0.0000001 mol/liter) of hydrogen ions.