Distillate – IGCSE Chemistry Definition
IGCSE Chemistry definition of distillate: the liquid collected after condensation during distillation. Covers context, purity, and exam tips for Cambridge 0620.
Published by IGCSEChemistry.com.my
Chemistry teaching team: K. S. Tan (15+ years teaching IGCSE Chemistry) and Ms Yash (10+ years teaching IGCSE Chemistry) and Ms Kartini (15+ years teaching IGCSE Chemistry).
Mapped to Cambridge IGCSE Chemistry 0620 (2026–2028). Last updated 2026-08-19.
The term “distillate” is the counterpart of residue and filtrate — it names the specific product of a distillation process. Using the correct terminology in your answers demonstrates practical understanding.
The 0620 definition
The distillate is the liquid collected after condensation in a distillation process. It is the substance that evaporated from the mixture and was then condensed back to a liquid in the condenser.
Distillate in context
During distillation, the mixture is heated. The component with the lowest boiling point evaporates first, passes through the condenser, and is collected as the distillate.
| What stays behind | What is collected |
|---|---|
| Non-volatile solute (e.g. salt) | Distillate (e.g. pure water) |
| Higher-boiling-point liquids | Lower-boiling-point liquid as distillate |
Examples
Simple distillation of salt water
- The solution is heated; water evaporates at 100 °C
- Water vapour condenses in the condenser
- Distillate = pure water
- Salt remains in the flask
Fractional distillation of crude oil
- Different fractions evaporate at different temperatures
- Each fraction condenses and is collected at the level matching its boiling point
- Distillate = the collected fraction (e.g. petrol, kerosene)
Purifying ethanol from fermentation
- The fermentation mixture contains ethanol, water, and yeast
- Heat to 78 °C (ethanol boils before water at 100 °C)
- Distillate = ethanol (with some water)
Worked exam question
A student distils seawater. (a) Name the liquid collected in the beaker. [1] (b) Suggest how the student could confirm the distillate is pure water. [1]
Mark scheme
(a) The distillate / pure water [1]
(b) Measure its boiling point — pure water boils at exactly 100 °C [1] (OR test that it leaves no residue when evaporated)
Common exam mistakes
- Confusing the distillate with the residue left in the flask — the distillate is collected after condensation, not what remains behind.
- Saying the distillate is always water — it is whatever substance evaporates and condenses. In ethanol distillation, the distillate is ethanol.
- Forgetting that the condenser is essential for obtaining the distillate — without it, the vapour escapes and is lost.
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