Acidity and alkalinity of a solution can be expressed with the value of
pH.
The pH scale
ranges from the highest acidity of 0 to the highest alkalinity of 14. A solution
with a pH of 7 is neutral. Healthy blood pH is 7.365, the pH of spinal
fluid is 7.4, and the saliva pH is 7.4.
In the absence
of oxygen, glucose undergoes fermentation to lactic acid.