DRAFT: This module has unpublished changes.
- Test Tubes (13), 10-mL
- Test Tube Rack
- Pipets (13), 1-mL, disposable
- Stirring Rods
- Masking Tape
- 0.2 M Sodium Sulfate, 10 mL
- 0.2 M Monopotassium Phosphate, 5 mL
- 0.2 M Sodium Nitrate, 5 mL
- 0.2 M Sodium Chloride, 5 mL
- Unknown anion solution #1, 20 mL
- Unknown anion solution #2, 20 mL
- 0.2 M Barium Nitrate, 5 mL
- Saturated Iron(II) Sulfate, 2 mL
- 0.1 M Silver Nitrate, 5 mL
- 6 M Nitric Acid, 5 mL
- 5 M Ammonia, 5 mL
- 3 M Sulfuric Acid, 5 mL
- Concentrated Sulfuric Acid, 2 mL
- Deionized Water
- Prepared a set of 5 test tubes. Cleaned them and set them in the test tube rack. Labeled 4 of them 1-4, and the 5th "Unknown #1"
- Labeled 6 disposable pipes, identically to the test tubes.
- Repeated, preparing a similar set of test tubes for "Unknown #2".
- Added 5 drops of the following substances to the associated test tube as follows:
- (Note: Unknown solutions each received 15 drops.)
- Added 5 M ammonia to each, until basic.
- Added 3 drops of Barium Nitrate to test tubes 1-4.
- Added Barium Nitrate drop by drop to the unknown solutions.
- Centrifuged the mixtures from the unknown solutions, to separate them into precipitate and supernatant. Separated them into different test tubes, labeled "Supernatant 1", and "Precipitate 1", and labeled them according to their respective unknown solution.
- Added 6 M Nitric Acid, drop by drop, to each solution from test tubes 1-4 which developed a precipitate.
- Added 6 M Nitric Acid, drop by drop, to Precipitate 1.
- Recorded partial or complete dissolution.
- Separated the unknown solutions into Precipitate 2 (if any), and Supernatant 2, and labeled according to unknown solution.
- Prepared another set of test tubes as outlined, (1-4) excepting unknown solutions.
- Diluted each with 1 mL of deionized water.
- Added 2 drops of Silver nitrate to each of the test tubes (1-4).
- Added ammonia to the solutions containing chloride, until the precipitate dissolved.
- Added 2 drops of Silver nitrate to each of the Supernatant 1 solutions.
- Added 2 drops of Silver nitrate to each of the Supernatant 2 solutions.
- Added 10 drops of 0.2 M Sodium nitrate to a clean test tube.
- Added 3 M Sulfuric acid, drop by drop while stirring, until the solution was acidic.
- Added 5 drops of saturated Iron(II) sulfate.
- Tilted the test tube to a 45º angle, and allowed 5 drops of Sulfuric acid to flow down the side of the tube, and float atop the solution, taking care not to mix the two.
- Recorded that the presence of nitrate ions was indicated by the formation of a brown ring between the layers of the two liquids.
- Repeated test, substituting 0.2 M Sodium nitrate with Unknown Solution #1, and then repeating again with Unknown Solution #2.