[SheffieldWednesday4ever]

Hi, this is one of the questions I'm trying to figure out.

So far, I've written the dissociations:

H3A   H + H2A^-  K(a1)
H2A^-   H + HA^-2 K(a2)
HA^-2     H + A^-3   K(a3)

I know Kb₃ is just A^-3 +H₂O   HA^-2 + OH^-

which I'm stuck...

Should I bring the values to? Or just use the Products/reactants eqb?

[Borek]

Write definitions of both Ka1 and Kb3. Not reactions, but definitions of dissociation constants.

[SheffieldWednesday4ever]

Thanks, but I've done that. So:

K_a1xK_b3=([H][H₂A]/[H₃A])x([OH][HA]/[A])

So, somehow the H2A H3A HA and A must cancel to 1? Would this be done with a mass balance then? I still haven't gotten there.

[Borek]

Your Kb3 is wrong.

[SheffieldWednesday4ever]

Thanks!