You want to form an insoluble precipitate of one ion without co-precipitating the other. A table of solubilities is helpful. If you add sulfate ions by adding some H2SO4 or Na2SO4, the Ba2+ ion will form an insoluble precipitate of BaSO4, but the Fe3+ ion does not form an insoluble sulfate. If you are doing this is a test tube, you would then centrifuge and decant the supernatant (liquid) from the solid BaSO4 at the bottom of the tube, and your two ions are now separated.  You could also make the solution basic by adding some ammonia solution. The hydroxide from the ammonia solution combines with the Fe3+ ion to form an insoluble precipitate of Fe(OH)3, but the Ba2+ ion will remain in solution since Ba(OH)2 is much more soluble. Steve |
Free Forum Hosting
Important Announcement
First 