8) Explain exactly how you would perform the following laboratory instructions:

-a) “Wash the organic layer with 5.0 mL of 1 M aqueous sodium bicarbonate.”
-b) “Extract the aqueous layer three times with 2 mL portions of methylene chloride.”

10) What should you do if there is some question about which layer is the organic one during an extraction procedure?

You must have something in your lab manual or notes about this. I don't understand what you don't understand about this.

8) a) To perform the instruction "Wash the organic layer with 5.0 mL of 1 M aqueous sodium bicarbonate," you would need the following materials and steps:

Materials:
- Organic layer (containing the desired organic compound)
- 5.0 mL of 1 M aqueous sodium bicarbonate solution
- Separatory funnel

Steps:
1. Set up a separatory funnel and place the organic layer in it. Ensure that the funnel is properly clamped and closed.
2. Add 5.0 mL of 1 M aqueous sodium bicarbonate solution to the separatory funnel, taking care not to introduce any air bubbles.
3. Carefully invert the separatory funnel several times to ensure thorough mixing of the organic layer with the sodium bicarbonate solution.
4. Allow the layers to separate. The organic layer, being less dense, will rise to the top, while the aqueous layer will settle at the bottom.
5. Gently open the stopcock or pour out the lower aqueous layer, being cautious not to disturb the organic layer.
6. Repeat the washing step (steps 2 to 5) if necessary in order to ensure complete removal of any residual impurities.

b) To perform the instruction "Extract the aqueous layer three times with 2 mL portions of methylene chloride," you would need the following materials and steps:

Materials:
- Aqueous layer (obtained after washing with sodium bicarbonate)
- 2 mL portions of methylene chloride
- Separatory funnel

Steps:
1. Set up a separatory funnel and carefully transfer the aqueous layer into it.
2. Add 2 mL of methylene chloride to the separatory funnel. Ensure that no air bubbles are introduced.
3. Close the separatory funnel and gently invert it several times to facilitate mixing of the aqueous layer with methylene chloride.
4. Allow the layers to separate. The denser layer (methylene chloride) will settle at the bottom and the less dense layer (aqueous layer) will rise to the top.
5. Open the stopcock or carefully pour out the lower methylene chloride layer, making sure not to disturb the aqueous layer.
6. Repeat steps 2 to 5 two more times to perform a total of three extractions with 2 mL portions of methylene chloride. This helps to ensure efficient extraction of the desired compounds from the aqueous layer into the organic solvent.

10) If there is some uncertainty about which layer is the organic layer during an extraction procedure, one should perform additional tests to determine the nature of the layers. Here are a few steps to follow:

1. Observe the density and color of the layers: Typically, the organic layer is less dense and may have a different color compared to the aqueous layer. The organic layer is usually located on the top.
2. Perform a solubility test: Take a small amount of each layer and add a known solvent for organic compounds (e.g., hexane, methylene chloride) to one test tube and a known solvent for aqueous compounds (e.g., water) to another test tube. Add a few drops of each layer to the respective solvents and observe if there is any dissolution. The layer that dissolves in the organic solvent is likely the organic layer.
3. Conduct a pH test: Use acid-base indicators to test the acidity/basicity of each layer. The organic layer is typically neutral or slightly acidic, while the aqueous layer may be basic if it contains sodium bicarbonate or other basic compounds.
4. Consult the experiment protocol or literature: If still unsure, refer to the experimental protocol or consult reliable sources or literature for information on the expected layers in the given extraction procedure.

8) To perform the laboratory instructions given,

a) "Wash the organic layer with 5.0 mL of 1 M aqueous sodium bicarbonate":
- Start by setting up a separatory funnel or a separating funnel.
- Add the organic layer (the layer containing the organic compound to be washed) into the funnel.
- Carefully measure out 5.0 mL of 1 M aqueous sodium bicarbonate solution.
- Add the sodium bicarbonate solution to the separatory funnel containing the organic layer.
- Close the funnel and gently shake it to mix the layers thoroughly.
- Allow the layers to separate into distinct organic and aqueous layers.
- Slowly open the stopcock or the stopper to release any pressure buildup caused by the reaction between the organic layer and sodium bicarbonate.
- Carefully drain off the lower aqueous layer from the funnel, ensuring that no organic layer is lost.
- Repeat this washing step if necessary to ensure efficient removal of any acidic impurities present in the organic layer.
- Observe the change in color or appearance of the organic layer after washing with sodium bicarbonate.

b) "Extract the aqueous layer three times with 2 mL portions of methylene chloride":
- After completing the previous step and separating the aqueous and organic layers, transfer the aqueous layer into a separate container.
- Measure out three portions of 2 mL of methylene chloride.
- Add the first portion of methylene chloride to the container with the aqueous layer.
- Close the container and gently shake it to facilitate the extraction of any organic compounds present in the aqueous layer.
- Allow the layers to separate, ensuring distinct separation between the organic and aqueous layers.
- Slowly open the container to release any pressure buildup.
- Carefully drain off the lower aqueous layer from the container, making sure not to lose any organic layer.
- Repeat this extraction process two more times using the remaining two portions of methylene chloride.
- After completing the extractions, you can collect the combined methylene chloride fractions for further analysis or processing.

Note: It is crucial to follow proper lab safety protocols, including wearing appropriate protective equipment (such as gloves and safety glasses) and working in a well-ventilated area.

10) If there is uncertainty about which layer is the organic layer during an extraction procedure, you can use several methods to determine the organic layer:

- Observe the physical properties: The organic layer is typically less dense than water and will float on top of the aqueous layer. You can visually inspect the layers to determine the one with the oily or immiscible appearance, indicating it is the organic layer.
- Use a water-sensitive indicator: Add a few drops of a water-sensitive indicator, such as phenolphthalein, to the mixture. Phenolphthalein remains colorless in the presence of water but turns pink in the presence of organic solvents. This color change can help identify the organic layer.
- Perform a solubility test: Take a small sample from the suspected organic layer and add it to a test tube containing a small amount of water. If the sample dissolves in water, it is likely part of the aqueous layer. If the sample remains insoluble or forms a separate layer, it is most likely part of the organic layer.

By using these methods, you can confidently determine which layer is the organic layer during an extraction procedure.