[qw1478]

Calculate the molar solubility of manganese(II) carbonate in a solution that is
buffered to a pH of 3.00.

I set up the equations:

MnCO3(s)<-->Mn + Co3 ksp = 2.2*10^‐11
CO3 + H3O <--> HCO3 + H2O = 1/Ka2=1/5.6*10^‐11
--------------------------------------------------------------
MnCO3 + H3O       <--> Mn +       HCO3     + H20 final k = .375
           1*10^-3             0               0
          -1*10^-3      +1*10^-3    +1*10^-3 (completion)
            +X                   -X                  -X     (back to eq.)


((1*10^-3)-x)^2
-------------------=.375  >>> X=2.7*10^-6
           X

So this means (1*10-3)-(2.7*10^-6) = [Mn] and [HCO3]= 9.9*10^-4

Now how do I find the molar solubility of MnCO3 from this. Please help.