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.
Basics Of pH Control. FUNDAMENTAL CONSIDERATIONS. By definition, pH is the negative logarithm of the. hydrogen-ion concentration in aqueous solution. This. means that a solution having a pH value of 4 has ten. times more hydrogen ions than a solution whose pH is. 5. For control systems neutralizing spent acids or. bases, pH value per se is of little consequence except.