We have to determine which of the two given substances (PbCO3 or BaCrO4) has a higher molar solubility.
We can look up the Ksp values of both substances on the internet or in a textbook.
Ksp for PbCO3 = 7.40×10-14
Ksp for BaCrO4 = 1.17×10-10
For each pair of compounds, use Ksp values to determine which has the greater molar solubility.
PbCO3 or BaCrO4