Aim: To separate a mixture of miscible liquids with different boiling points.
Principle: The fractionating column provides a temperature gradient. The liquid with the lower boiling point vaporises first, rises up the column, and is collected. The higher boiling-point liquid remains.
Example: Ethanol (78°C) + Water (100°C) mixture. Ethanol distils first.
• Ethanol and acetone are highly flammable — heat with an electric mantle or water bath, never a naked flame near the vapour.
• Their vapours are harmful and can form flammable mixtures with air — work in a well-ventilated area/fume cupboard.
• Steam and hot glassware scald; add anti-bumping granules and never seal the apparatus (pressure build-up).
• Connect the condenser water in at the bottom and out at the top; check joints before heating.
• Collect the flammable distillate away from heat sources; wear goggles.
Use the boiling points to predict, then lock it in.