Beginner Topic 898 of 1102 Analytical, Lab & Spectroscopy
Distillation
Separating liquids by differences in boiling points.
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In-depth explanation of Distillation
Distillation separates the components of a liquid mixture by heating it so the more volatile component vaporizes preferentially, then cooling and condensing the vapour to collect the distillate. The separation depends on differences in boiling points, and simple distillation works well when the boiling points differ by more than about 25 C. It is also used to separate a volatile liquid from nonvolatile solids, such as obtaining pure water from a salt solution. Boiling chips or stirring prevent bumping by providing nucleation sites for smooth boiling. A thermometer at the side arm measures the temperature of the vapour reaching the condenser. The process is energy intensive, so it is weighed against other separation methods.
Going deeper: Distillation
Key ideas: Set the thermometer bulb level with the side-arm opening, put water in at the bottom of the condenser and out at the top, add boiling chips before heating, and never distil to dryness. Collect the fraction that distils at a steady temperature. Distilling under reduced pressure lowers boiling points by tens of degrees, which protects heat-sensitive compounds.
Common mistakes and connections: Typical errors include putting the thermometer too high (reading low), heating too fast so vapour and liquid do not equilibrate, closing the system (an explosion risk), and adding boiling chips to hot liquid. Simple distillation does not separate liquids with close boiling points. Connects to fractional distillation, vapour pressure, Raoult's law and purity checks by boiling point.
Visualization of Distillation
A liquid boils when its vapour pressure equals external pressure; water at 373 K is separated from dissolved salt because only the water vaporizes. The interactive lesson shows this as a live animation or chart.
Worked example and use case
Pure water is obtained by distilling seawater, leaving the salt behind in the flask.
Frequently asked questions about Distillation
What is Distillation?
Separating liquids by differences in boiling points.
Is Distillation a beginner, intermediate or advanced topic?
Distillation is a beginner topic in Analytical, Lab & Spectroscopy. It needs no earlier chemistry lessons and is a good starting point.
What should I learn before Distillation?
Study these earlier topics in Analytical, Lab & Spectroscopy first: Primary Standards, Volumetric Glassware, Filtration.
What comes after Distillation?
The next topics in Analytical, Lab & Spectroscopy are Fractional Distillation and Steam Distillation.
Can I practise Distillation with quizzes?
Yes. The interactive lesson includes a self-check question on Distillation, and the Analytical, Lab & Spectroscopy quiz draws on every topic in this area.
Where Distillation fits in Analytical, Lab & Spectroscopy
Distillation is topic 22 of 99 in Analytical, Lab & Spectroscopy.