To prepare a pure sample of barium sulfate (BaSO₄) in the lab using the provided reagents (solid sodium sulfate, barium carbonate, dilute nitric acid), you can follow these steps:
Materials Required:
- Solid sodium sulfate (Na₂SO₄)
- Barium carbonate (BaCO₃)
- Dilute nitric acid (HNO₃)
- Beakers
- Stirring rod
- Filtration setup (filter paper, funnel, conical flask)
- Bunsen burner or hot plate (optional, for drying)
- Weighing balance
- Mortar and pestle (optional, for grinding)
Procedure:
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Preparation of Barium Nitrate:
- Weigh an appropriate amount of barium carbonate (BaCO₃).
- In a beaker, slowly add dilute nitric acid (HNO₃) to the barium carbonate while stirring gently. The reaction will produce barium nitrate (Ba(NO₃)₂), carbon dioxide (CO₂), and water (H₂O).
- The reaction is as follows: \[ \text{BaCO}_3 (s) + 2 \text{HNO}_3 (aq) \rightarrow \text{Ba(NO}_3)_2 (aq) + \text{CO}_2 (g) + \text{H}_2\text{O} (l) \]
- Ensure that all the barium carbonate reacts. You can tell that the reaction is complete when no more gas bubbles are produced.
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Preparation of Sodium Barium Sulfate:
- In another beaker, dissolve an appropriate amount of solid sodium sulfate (Na₂SO₄) in a small amount of distilled water to make a sodium sulfate solution.
- Once both solutions (barium nitrate and sodium sulfate) are ready, slowly add the sodium sulfate solution to the barium nitrate solution while stirring continuously. This will precipitate barium sulfate (BaSO₄) as a solid.
- The reaction is: \[ \text{Ba(NO}_3)_2 (aq) + \text{Na}_2\text{SO}_4 (aq) \rightarrow \text{BaSO}_4 (s) + 2 \text{NaNO}_3 (aq) \]
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Filtration:
- Set up the filtration apparatus using a filter paper and funnel over a conical flask.
- Pour the mixture through the filter paper. The insoluble barium sulfate will be collected on the filter paper, while the sodium nitrate (NaNO₃) solution will pass through.
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Washing the Precipitate:
- Wash the barium sulfate precipitate on the filter paper with distilled water to remove any remaining sodium nitrate and other soluble impurities. This should be done carefully to avoid losing the precipitate.
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Drying the Precipitate:
- Transfer the collected barium sulfate to a clean, dry beaker or dish.
- If desired, dry the barium sulfate using a Bunsen burner or hot plate (keep temperature low to avoid decomposition). Alternatively, air-drying can be performed by leaving it in a warm, dry place.
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Characterization (optional):
- You may want to check the purity of the barium sulfate by examining its characteristics (e.g., solubility tests, X-ray diffraction).
Conclusion:
By following these steps, you can prepare a pure sample of barium sulfate in the lab using barium carbonate and sodium sulfate along with dilute nitric acid. The resulting barium sulfate will be a white, insoluble solid.
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