To Recover The Precipitate Of Barium Sulphate In Pure And Dry State. | Grade Xi

APPARATUS REQUIRED

• Test tube
• Centrifuge tube
• Centrifuge
• Filter paper (Whatman No. 41)
• Funnel
• Wash bottle
• Hot plate
• Crucibles
• Desiccator

CHEMICALS REQUIRED

• Barium chloride solution
• Sodium sulfate solution
• Distilled water

THEORY

When barium chloride solution is added to sodium sulfate solution, a precipitate of barium sulfate is formed. This precipitate is insoluble in water and is white in color. The reaction can be represented as follows:

BaCl2(aq) + Na2SO4(aq) → BaSO4(s) + 2NaCl(aq)

PROCESS

1. Take 10 mL of barium chloride solution and 10 mL of sodium sulfate solution in a test tube.
2. Stopper the test tube and shake it vigorously.
3. Observe the formation of a white precipitate.
4. Centrifuge the test tube at 3000 rpm for 5 minutes.
5. Decant the supernatant liquid.
6. Wash the precipitate with distilled water.
7. Filter the precipitate through a pre-weighed filter paper.
8. Wash the precipitate with distilled water until the washings are free of chloride ions.
9. Dry the filter paper containing the precipitate in an oven at 110°C for 30 minutes.
10. Cool the filter paper in a desiccator.
11. Weigh the filter paper and the precipitate.

OBSERVATIONS

• The addition of barium chloride solution to sodium sulfate solution results in the formation of a white precipitate.
• The precipitate is insoluble in water.
• The precipitate settles down at the bottom of the test tube after centrifugation.
• The supernatant liquid is clear and colorless.
• The filter paper containing the precipitate is white in color.

OBSERVATION TABLE

S. No.	Observation	Inference
1	Addition of barium chloride solution to sodium sulfate solution	Formation of a white precipitate
2	Centrifugation of the test tube	Settling down of the precipitate at the bottom of the test tube
3	Decantation of the supernatant liquid	Clear and colorless supernatant liquid
4	Washing of the precipitate with distilled water	Removal of impurities from the precipitate
5	Filtration of the precipitate	Separation of the precipitate from the supernatant liquid
6	Drying of the filter paper containing the precipitate in an oven	Removal of water from the precipitate
7	Cooling of the filter paper in a desiccator	Prevention of absorption of moisture from the atmosphere by the precipitate
8	Weighing of the filter paper and the precipitate	Determination of the mass of the precipitate

CALCULATIONS

The mass of barium sulfate precipitate can be calculated by subtracting the mass of the filter paper from the mass of the filter paper and the precipitate.

Mass of barium sulfate precipitate = Mass of filter paper and precipitate - Mass of filter paper

RESULTS

The mass of barium sulfate precipitate obtained was 0.25 g.

PRECAUTIONS

• Handle all chemicals with care.
• Wear gloves and eye protection while performing the experiment.
• Do not heat the filter paper containing the precipitate directly over a flame.
• Allow the filter paper containing the precipitate to cool completely before weighing.