What is the pH?

The pH is a measure of acidity or the ability to neutralize acids that a chemical solution possesses. pH stands for hydrogen potential (number of hydrogen ions), & varies from 1 to 14, with one to six being an acidic pH, number seven a neutral pH, and from eight to fourteen alkaline pH (that means that it is capable of neutralizing acids and their effects).

Based on the Brönsted and Lowry theory [acid-base theory], acids are substances capable of giving a proton (H⁺) and bases are capable of accepting them. Acids have substances that are opposite to them, known as alkalis or bases, and when they come into contact with an acid they lose their properties and form a salt.

So the above is understood as a proton transfer relationship. And therefore the pH is tied to the hydrogen concentration.