Question

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

• A. Difference in their boiling points is greater than ${25}^{\circ }C$.
• B. They decompose and form other compounds.
• C. Difference in their boiling points is not greater than ${25}^{\circ }C$.
• 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 ${25}^{\circ }C$.

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

• It does not decompose while heating.
• The difference between the boiling points of miscible liquids should be sufficient (> ${25}^{\circ }C$).

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