pKa of carbonic acid
Closed this issue · 2 comments
In the carbonic acid example of the README, the pKa values of H2CO3 are given as [3.6, 10.32] and the pH of 0.01 M is computed to be 2.834.
According to this list the pKa values should be [6.35, 10.33].
Using these values gives a pH of 4.176 which is consistent with the value of 4.18 for 10 mM given here.
Is it just a typo?
According to Refs [1] and [2] (which are old, but whose results have been confirmed in more recent work), the pKa's of carbonic acid in water at 298K are indeed 6.35 and 10.33 (temperature-dependent). It must be a typo or an erroneous source.
[1] H. S. Harned, S. R. Scholes Jr. “The Ionization Constant of HC03- from 0 to 50°.” J. Am. Chem. Soc. 1941, 63,1706
[2] H. S. Harned, R. Davis. “The Ionization Constant of Carbonic Acid in Water and the Solubility of Carbon Dioxide in Water and Aqueous Salt Solutions from 0 to 50°.” J. Am. Chem. Soc. 1943, 65 , 2030