How to Calculate Theoretical H3O

Calculating the H3O concentration in any water solution is relatively easy.
••• Acid image by Yuriy Rozanov from

In pure water, a small number of the water molecules ionize, resulting in hydronium and hydroxide ions. A hydronium ion is a water molecule that has taken on an extra proton and a positive charge, and thus has the formula H3O+ instead of H2O. The presence of a large number of hydronium ions lowers the pH of a water-based solution. pH is a measure of the acidity of a solution and is a logarithmic reflection of the amount of hydronium ions present in the solution. pH measurements can range from 0 to 14. You can use this information to calculate the theoretical concentration of hydronium ions in any solution.

    Note the pH of the solution in question. Usually you can read the label of the solution or look up the pH of common substances in a chemistry book or online reference. If it is an unknown solution with an unknown pH, use a pH meter or conduct a chemical titration to determine its pH.

    Solve the pH equation for the "hydronium ion concentration" variable.

    pH = - log (Hydronium Ion Concentration), so

    Hydronium Ion Concentration = 10^(-pH)

    (^ = symbol that means to the power of)

    Plug the pH value of your solution into the equation to reveal the concentration of hydronium ions in the solution. For example, consider a solution with a pH of 2.

    Hydronium Ion Concentation = 10^-2 = 0.01 moles/liter

    There are 0.01 moles of hydronium ion per liter of your solution.

Related Articles

How to Identify if a Solution Is Neutral, Base or Acidic
How to Find Hydroxide Ion Concentration
How to Calculate Ka From Ph
How to Calculate Melting & Boiling Points Using Molality
How to Calculate Bicarbonate Concentration
How to Find the Concentration When You're Given the...
How to Identify if a Solution Is Neutral, Base or Acidic
How to Solve a Parabola
How to Calculate Buffers
How to Calculate the K Value on a Titration Graph
How to Calculate Concentration From Density
Water pH & Pollution
How to Calculate the pH of a Strong Acid
How to Find the Height of a Rectangular Pyramid
How to Calculate Particle Concentration
How to Calculate Milliamps
How to Calculate Hydrogen Ion Concentration
How to Calculate Percent Dissociation
How to Determine If Salts Are Acidic or Basic