What is the exact meaning of the term pH?
pH as a term was coined by Sorensen in 1909. He described the concentration of hydrogen ion as a logarithmic scale which he called “Pondus Hydrogeni” or the exponent of hydrogen. pH is a quantitative unit of measure which describes the degree of acidity or alkalinity of a substance. It is measured on a scale of 0 to 14. The term pH is derived from “p” the mathematical symbol of the negative logarithm, and “H” the chemical symbol of Hydrogen. The formal definition of pH is the negative logarithm of the hydrogen ion concentration i.e. pH = -log10[H]+ In practice it is the hydrogen ion activity which is measured rather than its concentration.
