Calculate the maximum concentrations of Pb+ that can exist in 3.0 x 10(-2)M Na2SO4 without forming a precipitate.
PbSO4==>Pb^+2 + SO4^=
Ksp = (Pb^+2)(SO4^=)
Look up Ksp for PbSO4. Plug in SO4^= from Na2SO4 and calculate (Pb^+2) which will be equal to (PbSO4). Post your work if you get stuck.