To determine the amount of Cl in 3000 mL of an unknown solut

To determine the amount of Cl^- in 30.00 mL of an unknown solution, an excess of AgNO3 is added. The AgCl precipitate was found to weight 0.3912 g. What is the concentration of Cl^-(ppt) in the original solution? Assume a density of 1.00 g/ml for the original solution.

Solution

No of mol of AgCl formed = w/M = 0.3912/143.32 = 0.00273 mol

No of mol of Cl- in original solution = 0.00273 mol

amount of cl- in solution = 0.00273*35.5 = 0.097 g

mass of solution = v*d

                 = 30*1

                 = 30 g

partsperthousand(PPT) = mass of solute/mass of solution*100

                     = 0.097/30*100

                     = 0.323 ppt