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Chemistry Forums for Students => High School Chemistry Forum => Chemistry Olympiad and other competitions => Topic started by: willy.Jonathan.12 on September 02, 2014, 05:41:31 PM

Title: Dissociation degree calculation from Ka1 Ka2 and H+
Post by: willy.Jonathan.12 on September 02, 2014, 05:41:31 PM

Hello
My task is to express dissociation degree for fully dissociated form of diprotoic acid in general as a function of Ka1 Ka2 and [H+].

I know that
Ka1=[H+]*[HA-]/[H2A]
Ka2=[H+]*[A2-]/[HA-]
[HA-]+[A2-]=[H+]

diss degree=[A2-]/(HA-]+[H2A]+[A2-])

But I have no idea how to exchange all this things with only Ka1 Ka2 and [H+]
Can someone help me with that ?

Title: Re: Dissociation degree calculation from Ka1 Ka2 and H+
Post by: Borek on September 02, 2014, 06:16:01 PM

See

http://www.chembuddy.com/?left=pH-calculation&right=pH-polyprotic-acid-base

(while it aims at something else, it contains all formulas you need).