How many milliliters of 0.540 M sodium sulfate solution would be needed to precipitate the calcium ion from 60.0 mL of 0.180 M CaCl2 solution?
CaCl2 + Na2SO4 ==> CaSO4 + 2NaCl
mols CaCl2 = M x L = ?
Convert to mols Na2SO4. That is
?mols CaCl2 x (1 mol Na2SO4/1 mol CaCL2) = ?mols CaCl2 x 1/1 = ?
Then M Na2SO4 = mols/L. YOu know M and you know mols, solve for L and convert to mL.