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 pH level of a solution is nothing more than the concentration of positively charged ions in that substance. These positively charged particles are expressed on a pH scale, which ranges from 0 (acid) to 14 (alkaline). A liquid with a pH level of 7 is called neutral; non acidic and non alkaline.