Answer
See the answer below.
Work Step by Step
In all cases except c, solubility as a function of Ksp is the same for both compounds, so the one with the higher Ksp is the more soluble;
a) AgSCN, 1.0e-12 vs 5.4e-13 for AgBr
b) SrSO4, 3.4e-7 vs 5.6e-10 for SrCO3
c) AgI: $Ksp=[Ag^+][I^-]\rightarrow Ksp=s^2\rightarrow s=9.22\dot{}10^{-9}\ M$
PbI2: $Ksp=[Pb^{2+}][I^-]^2\rightarrow Ksp=s\dot{}(2s)^2\rightarrow s=1.35\dot{}10^{-3}\ M$
PbI2 is more soluble.
d) MgF2, 5.2e-11 vs 5.3e-11
