We must be familiar with the concept of pH.
In addition to the pH of the solution, the human body also has the pH, which is judged by the pH of the body fluid (Body fluid or Bodily fluid).
The pH value of 7 is neutral, <7 is acidic, >7 is alkaline, the normal pH value of human tissue should be 7-7.4.
pH, also known as pH value, hydrogen ion concentration index, acid-base value, is a scale of hydrogen ion activity in a solution, that is, a measure of the acidity and alkalinity of a solution in the usual sense.
There is no doubt that the "H" in "pH" stands for hydrogen ion (H+), but the source of p is controversial, and there is no agreement.
The first one is called p stands for German "Potenz", which means strength, intensity, and one says it stands for French puissance, which also means "strength, strength";
The second is called pH, which stands for the Latin word "pondus hydrogenii", which is "quantity of hydrogen".
The third thinks that p is just a symbol chosen by Sorensen at will, because he also used q.
In today's chemical world, p is added in front of a dimensionless quantity to indicate the negative logarithm of the quantity, so p should be lowercase.