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 simple distillation is typically used to separate components with a large difference in boiling points, such as ethanol and water. However, in the case of a clarified reaction mixture containing ethanol and water, simple distillation may not be effective in achieving a complete separation.
The reason is that the clarified reaction mixture may still contain impurities or other volatile substances that could have similar boiling points to ethanol. These impurities can create an azeotropic mixture, which behaves as a single compound with a constant boiling point, making it difficult to separate the ethanol from the water using simple distillation alone.
To overcome this limitation, fractional distillation is employed. Fractional distillation involves using a fractionating column, which provides more efficient separation of components by allowing repeated vaporization and condensation. In this process, the column provides a larger surface area for vapor-liquid contact, allowing the separation of more volatile components like ethanol from less volatile ones like water.
By using a fractionating column, the repeated vaporization and condensation steps help to break the azeotropic behavior and allow for a more complete separation of ethanol from water. This is achieved by fractionating the vapor mixture based on their differing boiling points while passing through the column. As a result, the ethanol can be collected separately from the water, leading to a more efficient and complete separation.
So in summary, simple distillation may not effectively separate ethanol from water in a clarified reaction mixture due to the presence of impurities or azeotropic behavior. Fractional distillation, on the other hand, utilizes a fractionating column to achieve a more complete separation by facilitating repeated vaporization and condensation, thereby overcoming the limitations of simple distillation.