Why is it not possible to achieve a complete separation of the ethanol from the water in the clarified reaction mixture via simple distillation?
I'm not sure about this because I thought the difference between fractional (what was done) and simple distillation is that fractional distillation is performed to purify mixtures in which the components have close boiling points. However, ethanol has a boiling point of 78.4 degrees Celsius and water has a boiling point of 100 degrees Celsius, which really are not close. Please Help!
You are correct that the boiling points of ethanol and water are not very close. However, even though the boiling points differ, a simple distillation process would still not be able to achieve a complete separation of ethanol from water in this case.
Simple distillation works by heating a mixture to its boiling point and collecting the vapor that is produced. The vapor contains primarily the component with the lower boiling point. In the case of ethanol and water, the ethanol would evaporate first since it has a lower boiling point.
However, during a simple distillation process, the vapor collected would still contain some amount of water along with ethanol molecules. This is because ethanol forms an azeotrope with water. An azeotrope is a mixture of two or more liquids that behaves as if it were a single component, meaning the composition of the vapor and the liquid will be the same.
In the case of ethanol-water mixture, the azeotrope has a boiling point of around 78.2 degrees Celsius and contains about 95.6% ethanol and 4.4% water by weight. This means that even if you heat the mixture to its boiling point, the vapor collected will still contain some water along with ethanol. The distillation process is not capable of achieving a complete separation of the two components because they form an azeotrope.
To achieve a more complete separation, a different method called fractional distillation is needed. In fractional distillation, a fractionating column is used to enhance the separation process. The column provides a larger surface area for vaporization and condensation to occur, allowing for multiple distillation stages and a better separation of the components with different boiling points.
So, in summary, the inability to achieve a complete separation of ethanol from water via simple distillation is due to the formation of an azeotrope between the two components. To achieve a more efficient separation, fractional distillation, rather than simple distillation, is required.