Consider a solution that contains Ag+ , Ba2+, and Pb2+ each at a concentration o
ID: 840665 • Letter: C
Question
Consider a solution that contains Ag+ , Ba2+, and Pb2+ each at a concentration of .2M?
a) You add NaCl until the concentration of Cl- is 5.0 x 10^-3 M. A white precipitate forms. How do you determine whether that precipitate was AgCl or PbCl2?
b) If you seperated the supernatant from above and treated it with 3.0 M HCl would a precipitate of PbCl2 be observed? Justify answer mathmatically.
c) if you took the supernatant from above and treated it with 3 M Na2SO4, would you expect a precipitate to form? What would be the identity of the precipitate?
Explanation / Answer
The Ksp od AgCl is very much smaller than that of PbCl2. One would expect the AgCl to begin to precipitate first. AgCl is soluble in [NH4]OH.
PbCl2 would precipitate. Look at the Ksp for your math.
BaSO4 is the precipitate.