when two layers form during an ether/water extraction, what would be an easy, convenient way to tell which layer is which if the densities were not available?
Bob Pursley brings up an important point. One solution is to add water, dropwise, and see if it floats or sinks to the bottom.
If the densities of the layers are not available, you can still distinguish between them using a simple yet effective method called the "shake test." Here's how you can perform it:
1. Take a small amount of the mixture and transfer it to a separate container.
2. Add a small volume of a soluble dye, such as food coloring or a dye solution, to the mixture.
3. Securely close the container and vigorously shake it for a few seconds.
4. Allow the mixture to settle undisturbed for a brief period, typically around 5-10 minutes.
5. Observe the container carefully.
The layer that has the dye dissolved in it will exhibit a visible color, distinguishing it from the other layer. This indicates that the layer with color is the one that contains the solvent you added the dye to. Typically, the organic layer (ether in this case) will be on the top, while the aqueous layer (water) will be at the bottom.
Remember to perform this test on a small sample rather than the whole mixture to avoid wasting resources in case the identification is incorrect.
To determine which layer is which during an ether/water extraction when densities are not available, you can use the solubility of the compounds in each solvent. Here's a step-by-step process to help you identify the layers:
1. Observe the appearance: Take a close look at the two layers formed after the extraction. Note any visible differences in color, transparency, or consistency.
2. Add a polar solvent: Take a small amount of each layer and transfer it to separate test tubes. Add a polar solvent, such as water or ethanol, to one of the test tubes and gently mix.
3. Observe for dissolution: If a compound in the layer dissolves or forms a homogeneous mixture with the added polar solvent, then that layer is likely the aqueous layer (water layer). This suggests that the compound is polar and hydrophilic, meaning it will dissolve in a polar solvent like water.
4. No dissolution with polar solvent: If the compound does not dissolve or only partially dissolves in the polar solvent, it suggests that the layer is the organic layer (ether layer). This indicates that the compound is nonpolar and hydrophobic, meaning it prefers the nonpolar solvent like ether.
By observing the appearance and testing the solubility of the compounds in a polar solvent, you can distinguish between the ether and water layers even if the densities are not available.
Well, don't stick a lighted match into the top layer, or near it.
But my question really would be this...why on Earth would anyone be using Ether who did not know its detailed characteristics, especially its vapor characteristics.
I personally very keen on potential hazards being well known before students even associate with chemicals.