How will you separate two miscible liquids?

We separate two miscible liquids mainly by distillation, and if their boiling points are close, by fractional distillation; special cases use steam distillation or azeotropic distillation.

Because miscible liquids form a single homogeneous phase, we cannot use a separating funnel (that method works for immiscible liquids like oil and water). Instead, we rely on differences in boiling point and vapor pressures. In simple distillation, the mixture is heated so that the more volatile component vaporizes first. The vapor is then condensed in a cooled tube and collected as the distillate. The less volatile liquid remains in the flask as the residue.

Steps for fractional distillation (close boiling points):

1. Set up a round-bottom flask with the liquid mixture, a fractionating column (packed with glass beads), a thermometer at the head, a condenser, and a receiver.
2. Heat gently. Vapors rise and repeatedly condense and revaporize on the packing. The more volatile component enriches at the top.
3. Collect the fraction over the temperature range where the thermometer stays nearly constant (plateau). This is the first component.
4. As temperature rises to the next plateau, switch receivers and collect the second component.