Question

Determine the molar solubility (S) of Ag2CO3 in a buffered solution with a pH of 3.378 using the systematic treatment of equilibrium. Ksp(Ag2CO3) = 8.46 × 10–12; Ka1(H2CO3) = 4.45 × 10–7; Ka2(H2CO3) = 4.69 × 10–11.

Answer 1

Ag2CO3 ==> 2Ag^+ + CO3^2- Write Ksp
H2CO3=> H^+ + HCO3^- Write k1 expression
HCO3^-=>H^+ + CO3^2-.Write k2 expression
H^+ = 4.187E-4
Solubility = S, then
S = (CO3^2-) + (HCO3^-) + (H2CO3)
Substitute H^+ into k2 expression and solve for HCO3^- in terms of CO3^2-; i.e., (HCO3^-) = (H^+)(CO3^2-)/k2 = ?

So the same for k1 and solve for H2CO3 in terms of HCO3^- and k1

Plug values into HCO3^- and H2CO3 and CO3^2- into the S equation, solve for CO3^2- in terms of S, plug all of that into Ksp expression and solve for S.