Calculate the ratio of each component to the 【DIC】, which is the carbonic acid component dissolved in water of any pH.

 The procedure is exactly the same as before. Again, write down the equation for the dissociative equilibrium,

and transform the formula into the following form: [Each carbonic acid component] = ~~~~ ← (Formula for K1, K2, [H+]) x [DIC]).

The formula transformations are [H2CO3] = , [HCO3-] = , [CO32-] = , in this order: Equation (6), Equation (7), and Equation (8).


Substitute the values of K1 and K2, and [H+] in 0.1 increments of pH from pH 2 to 12.



Substituting K1 = 10-5.882 and K2 = 10-9.035 into Equations (6) through (8)

Then, graph this. (Below, the vertical axis is 1-100 (%), but could be 0-1)


At pH<4, most of the carbonic acid component is present as H2CO3, and at pH>11, most is present as CO32-.

最終更新日時: 2023年 08月 8日(火曜日) 19:43