Question

A mixture of two miscible liquids (acetone and methanol) cannot be separated by simple distillation because:

• A. Difference in their boiling points is greater than 25ºC.
• B. They decompose and form other compounds.
• C. Difference in their boiling points is not greater than 25ºC.
• D. Both of them sublime at a very low temperature.

Answer 1

The correct option is C Difference in their boiling points is not greater than 25ºC.

The conditions that are essential for a miscible liquids to be separated by simple distillation column are:

* They do not decompose while heating.
*The difference between the boiling points of miscible liquids should be sufficient (> 25ºC).

The boiling points of acetone and methanol are 56ºC and 64.7ºC respectively which concludes that the difference in their boiling points is not greater than 25ºC and hence cannot be separated by simple distillation. Instead we can use fractional distillation to separate this mixture.