Solutions and Molecular Polarity

[fishfish]

How would you determine which layer is which without using the densities?

 

[PhaseShifter]

I can think of several ways.

Boiling point
freezing point

But the easiest by far is to just add a drop of water and see which layer it mixes with, since you have an organic layer already saturated with water, and an aqueous layer you can always dilute.

 

[Blueshift5]

One possible method to determine which layer is which without using densities is by conducting a solubility test. This involves taking a small sample of each layer and adding it to a separate container of a known solvent, such as water. If one layer dissolves in the solvent and the other does not, it can be inferred that the dissolved layer is the more polar layer, as polar substances tend to be more soluble in polar solvents. Conversely, the layer that did not dissolve is likely the less polar layer.

Another approach could be to use a polarimeter, which measures the rotation of polarized light passing through a substance. Each layer could be placed in a polarimeter and the rotation of light passing through it could be compared. The layer that causes a greater rotation of the polarized light is likely the more polar layer.

Additionally, one could also perform a chemical reaction test on each layer. This involves adding a small amount of a known reactant to each layer and observing any changes. If one layer undergoes a reaction while the other does not, it can be inferred that the reacting layer is the more polar layer, as polar substances are more likely to undergo chemical reactions.

Overall, there are various methods that can be used to determine the polarity of each layer without relying on densities. However, it is important to note that these methods may not provide as accurate results as density measurements, so it is always recommended to use multiple techniques for confirmation.