Question

Calculate the molar solubility of BaSO4 in a solution
in which [H3O+] is 3.5 M. Ksp(BaSO4) = 1.1 x 10^-10, Ka(HSO4)=1.02 x 10^-2

Answer 1

BaSO4 ==> Ba^2+ + SO4^2- (eqn 1) and
SO4^2- + H^+ ==> HSO4^- (eqn 2)eqn 2
Let S = solubility so
(Ba^2+) = S and (SO4^2-) +(HSO4^-) = S
You want to find S. You know k2 for HSO4^- which is
0.0102 = (H^+)(SO4^2-)/(HSO4^-). You know(H^+) and k2 from the problem so you calculate (HSO4^-) = (H^+)(SO4^2-)/k2 = ? and plug that into eqn 2, solve for S and plug that into Ksp expression for BaSO4. Solve for S and that's it. Post your work if you get stuck.