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Acidity of a solution

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Acidity of a solution diagram
The pKa of a substance is a logarithmic scale that relates its dissocation constant to give acid in aqueous solution. Low (i.e. negative) numbers relate to strong acids. Together with the total substance concentration it allows an approximate pH to be calculated.

Concentration of H+
Approx. pH
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Enter the total concentration of the acidic substance and its pKa. Note that this calc is not suitable for multiprotic acids such as sulfuric acid.
For reference, some known values of pKa include: Perchloric acid (-10); hydrochloric acid (-8); nitric acid (-2); vitamin c (4.04); benzoic acid (4.20); acetic acid (4.76); pyridinium (5.21); ammonium (9.25); phenol (9.99); triethylammonium (11.01); water (15.76); ethane (50).