Assuming the sample is pure sodium sulfate, how many mL of 5% BaCl2.2H20 solution would be required to precipitate the sulfate. Density of barium shloride solution of 1.00 g/mL.

Answer 1

That all depends upon how much of the Na2SO4 is involved. moles Na2SO4 = grams/molar mass

Determine the M of the BaCl2.2H2O soln. 5% means you have 5.0 g BaCl2.2H2O/100 mL. moles = grams/molar mass; then M BaCl2.2H2O = moles BaCl2.2H2O/0.1L = ?M.

Write the equation and convert moles Na2SO4 to moles BaCl2.2H2O. Then
M BaCl2.2H2O = moles Ba^2+ required/L soln and solve for L.