To calculate pH from molarity, take the negative logarithm of the molarity of the aqueous solution similar to the following equation: pH = -log(molarity). pH is the measure of how acidic or basic a substance is, which refers to the concentration of hydrogen atoms that are present. Molarity is the concentration of a particular aqueous solution in moles, also known as Avogadro's number, per liter.
An individual who already has the molarity of an aqueous solution can simply use a calculator with the molarity to determine what the pH of the solution. pH ranges from 0 to 14. A neutral pH, which is the pH of water, is 7.0 while a pH less than 7.0 is considered to be acidic. A pH above 7.0 is considered to be basic. Any solution that has a very acidic or basic pH is considered to be reactive, and will easily react with other molecules and elements found in various solution to produce different compounds.
The pH and pOH of an aqueous solution should equal to 14. This is to maintain the equilibrium of the ionization reactions that happen in the solution. In short, if the pH or the pOH of a solution is known, the other can be easily deduced through simple math.