Posted by Dan on .
How do I do this problem, I am very confused on how to even begin:
An aqueous solution contains 0.167 M ascorbic acid (H2C6H6O6) and 0.194 M hydroiodic acid.
Calculate the ascorbate (C6H6O62-) ion concentration in this solution.
[C6H6O62-] =? mol/L.
Ascorbic acid is a weak acid and ionizes partially. HI is a strong acid and ionizes 100%. The following is NOT the way it ionizes but it is a shortcut that can be used under some circumstances. This is one of them. To keep typing down I'll call ascorbic acid simply H2Asc
H2Asc ==> 2H^+ + Asc^2-
k1*k2 = (H^+)^2(Asc^2-)/(H2Asc)
You know H^+ from the HI (0.194 M) and you know H2Asc (0.167 M), look up k1 and k2 and solve for (Asc^2-).