An aqueous solution contains two solutes, A and B. A is soluble in hexane, B is not. Hexane is liquid at room temperature and does not mix with water. The density of hexane at room temperature is 0.7 gdm-3. Describe, giving full practical details, how you would produce a pure sample of solid A.
You need to read about extractions. Since A is soluble in hexane and B is not, you extract A with hexane (go through perhaps 2-3 extractions), then evaporate the hexane to provide pure solid A.
h2o+c5r
square root of 58*7=20.149441
To produce a pure sample of solid A from the aqueous solution containing solutes A and B, we can utilize the immiscibility of hexane and water and the solubility of A in hexane. Here is a step-by-step procedure to obtain a pure sample of solid A:
Materials required:
1. Aqueous solution containing solutes A and B
2. Hexane
3. Separatory funnel
4. Beaker or flask
5. Glass stirring rod
6. Funnel
7. Filter paper
8. Evaporating dish
Procedure:
1. Prepare a separatory funnel setup by attaching the separatory funnel to a glass stirring rod secured in a stand. Place a beaker or flask under the funnel to collect the hexane layer.
2. Add the aqueous solution containing solutes A and B to the separatory funnel. Ensure not to overfill the funnel, leaving enough headspace for shaking.
3. Add an appropriate volume of hexane to the separatory funnel. The volume of hexane should be sufficient to extract all solute A, but not too excessive to avoid large volumes of organic layer.
4. Close the separatory funnel tightly and shake it vigorously for several minutes. This allows for thorough mixing of the aqueous and organic phases, allowing the transfer of solute A into the hexane layer.
5. Allow the contents of the separatory funnel to settle. The mixture will separate into two liquid layers due to their immiscibility. The denser aqueous layer will be at the bottom, and the lighter hexane layer will be on top.
6. Gently open the stopcock of the separatory funnel, allowing the aqueous layer to drain out while carefully collecting the hexane layer in the beaker or flask placed below. Take caution not to let any of the aqueous layer pass through.
7. Transfer the collected hexane layer, which now contains solute A, into an evaporating dish.
8. Set up a well-ventilated area or fume hood to allow for safe evaporation of the hexane. This step is important as hexane is volatile and flammable.
9. Leave the evaporating dish exposed to open air. As the hexane evaporates, it will leave behind a pure sample of solid A.
10. If needed, to further ensure the purity of solid A, it can be washed with a suitable solvent like acetone to remove any remaining traces of hexane.
11. Once the hexane has completely evaporated, carefully collect the solid A using a funnel and filter paper to remove any impurities.
12. Allow the solid A to air dry, or if necessary, you can use a desiccator to remove any remaining moisture.
By following these steps, you will be able to produce a pure sample of solid A from the aqueous solution containing solutes A and B. Remember to prioritize safety precautions during the handling and disposal of hexane.