pH CALCULATOR

pH measures the acidity or basicity (alkalinity) of a solution on a scale from 0 to 14, with 7 being neutral. An acidic solution has a pH less than 7, while a basic solution has a pH greater than 7. Pure water is "neutral" with a pH of 7. As the pH decreases, the acidity of the solution increases. As the pH increases, the basicity (or alkalinity) of the solution increases. pH is a measure of the concentration of hydrogen ions (H⁺) or hydronium ions (H₃O⁺) in a solution. A higher concentration of H⁺ ions leads to a lower pH (more acidic) as the following equation demonstrates . . . .

pH = - log[H⁺]

pH is very important in scientific areas like chemistry, biology, and environmental science, as it affects chemical reactions, biological processes, and the quality of water.

While the calculation of pH is not mathematically challenging, the variety of solution mixtures one will encounter in the chemistry laboratory presents approximately 30 unique situations and approaches to determining the solution's pH.

Is the solution a strong (or weak) acid or base? (4 situations)

Are you diluting (adding water) to a strong (or weak) acid or base? (4 situations)

Are you reacting a strong (or weak) acid with a strong (or weak) base?
    What is "left over" after the reaction has gone to completion?
        Strong acid?
        Strong base?
        Weak acid?
        Weak base?
        Weak acid and weak base (a buffer solution)? (15 situations)

Are you adding a weak acid to a weak base and making a buffer solution? (1 situation)

Are you reacting a strong acid or strong base with a buffer solution?
    What is "left over" after the reaction has gone to completion?
        Strong acid and weak acid?
        Strong base and weak base?
        Weak acid?
        Weak base?
        Buffer solution? (6 situations)

Fortunately, the pH Calculator can guide you through these 30 calculations . . . . just select the starting "situation" and begin. It even checks your work.