Dilution of Bases and Acids

This tool allows the calculation of the pH values of diluted bases and acids. Please insert three values, the fourth will be calculated. Any of the four values ​​can be left blank. As a neutral dilution liquid (pH value 7), water is estimated. The calculated value is a good estimation.

Example: 25 percent acetic acid has a pH of 1.85. If you mix 100 milliliters of it with 200 milliliters of water, you get acetic acid with a pH of 2.33. The concentration of this acid is one third of the original acid because the amount has been tripled, i.e. 8.33 percent.

The pH value is calculated based on powers of ten. Every reduction of one represents ten times as many active positively charged hydrogen ions in the form of oxonium ions, H₃O⁺, and thus an acid that is ten times as strong. Every increase of one represents 10 times as many active negatively charged hydroxide ions, HO⁻, and thus a base that is ten times as strong. At the neutral value of 7, H₃O⁺ and HO⁻ ions are in balance.

pH values ​​are only suitable for diluted solutions and can range from 0 to 14. A more advanced but more complicated method is the evaluation based on the acid constant with the pK_s value, or the pK_b value for bases. For strong acids such as the so-called superacids, there is the calculation using the Hammett acidity function.

The pH value was introduced in 1909 by the Danish chemist Søren Peter Lauritz Sørensen as a hydrogen ion exponent. The definition has been further refined since then. The pH value has become part of everyday language, and you can find corresponding information on some foods and cosmetics, for example. pH skin-neutral (pH value 5.5) means something different than pH neutral (pH value 7), since human skin has an acid mantle.