If toluene (density 0.87) wre used to extract ethylene bromohydrin (density 2.41) from an aqueous solution,

a. Could you be certain that the organic solution would form the upper layer?
b. by what test could you identify the nonaqueous layer.

You would normally use an excess of the solvent (toluene) to perform the extraction if you were using a separating funnel. To be certain you would need to do quick calculation of the density of the expected mixture.

Just a minor point but the density of ethylene bromohydrin looks a little high at 2.41. I seem to remember dibromoethane being just over 2.0 so I would have expected this to be lower.

I would identify the aqueous layer with anhydrous copper sulfate (turns white to blue) or from the curvature of the interface between the layers.

a. To determine if the organic solution (toluene) would form the upper layer, we need to compare the densities of toluene and ethylene bromohydrin. In this case, toluene has a density of 0.87 g/mL, whereas ethylene bromohydrin has a density of 2.41 g/mL.

When two immiscible liquids are mixed, the liquid with the lower density typically forms the upper layer, while the liquid with the higher density forms the lower layer. In this scenario, since toluene has a lower density than ethylene bromohydrin, we can be certain that the toluene (organic solution) would form the upper layer.

b. To identify the nonaqueous layer (toluene) in this extraction process, you can perform a simple density test.

1. Take a small sample of the solution that has been extracted and place it into a test tube or a graduated cylinder.
2. Allow the liquid to settle for a few minutes so that any layers can separate.
3. Observe the sample closely. If two layers are present, the top layer will be the organic toluene layer, and the bottom layer will be the aqueous layer.
4. To confirm that the top layer is indeed toluene, carefully measure the density of that layer using a density meter or a densitometer. Compare the density value obtained to the known density of toluene (0.87 g/mL). If the measured density matches the known density of toluene, then you have identified the nonaqueous layer as toluene.

It is worth noting that this test only confirms the density of the organic layer, and further analysis may be required for a more definitive identification.