Ksp of BaCrO4 is 2 × 10−10 at room temperature. Calculate the mass of Barium chromate lost by washing with three litres of water. Will the loss in mass depend on the quantity of precipitate?
10.625 mg
BaCrO4 (s) ⇌ Ba2+ + CrO2−4
KSP = 2 × 10−10
∴ Solubility of BaCrO4 = √2 × 10−19 = 1.41 × 10−3
Concentration of barium chromate = 1.4 × 10−3
M. Mass of BaCrO4 = 253
1.4 × 10−7 moles of BaCrO4 = 1.4 × 10−3 × 253 g
= 1.4 × 10−3 × 253 × 1000 = 3.542 mg
for a single washing with one litre of water the mass of BaCrO4 lost = 3.542 mg
mass of Barium Chromate lost by washing with three litres = 3.542 × 3 = 10.626 mg
Loss of mass does not depend upon the quantity of the precipitate.