Distillation and vapor–liquid composition
Distillation uses vapor–liquid partitioning and condensation, with a limit at an azeotrope.
Key knowledge
Distillation separates components by forming vapor and condensing it. Where vapor and liquid have different compositions, the vapor can be enriched in the more volatile component. Fractional distillation provides repeated vapor–liquid contacts to increase separation. At an azeotropic composition and specified pressure, equilibrium vapor and liquid have the same composition; ordinary distillation then cannot enrich one component beyond that composition simply by adding more stages.
Conditions and scope
- Use the actual mixture's vapor–liquid equilibrium at the operating pressure; boiling-point differences alone do not guarantee purity.
- This states the separation principle, not apparatus instructions or a design calculation. Thermal decomposition, entrainment and finite separation efficiency can matter.
Sources · 3
References
Sources retain their recorded scope. A source link alone does not establish verification of every statement.
- Digital Lab Techniques Manual (2007), Distillation I: transcriptSarah Tabacco and Aayesha Siddiqui · MIT OpenCourseWareTeaching resource · PDF
- CHE 396 Senior Design: Distillation, introduction and limitations (University of Utah course archive)Andreas Linninger, Michael Redel, Alycia Novoa, Tanya Goldina and Michelle EnglertCourse notes · PDF
- Chemistry XII: SolutionsNCERTTextbook chapter · PDF
Evidence and review
Vaporization/condensation, repeated fractional contacts and the equal-composition azeotropic limit.
2026-10-10 · Independent Mathematics and Information editor (AI editorial/source review; not the Chemistry/Biology/Earth author). The specified introductory inventory has no unresolved demonstrated material gap after the changes and body-based reuse. Existing advanced references retain their historical scoped approvals. English-only reference prose and explicit Lithuanian-translation-pending status are preserved.
Foundational review
2026-10-10 · Independent AI editorial inspection of this new compact reference entry, its equations, applicability, sources and knowledge connections.
Sources from other places
Agreement within this scope
Equal liquid/vapour composition at an azeotrope limits fractional separation.
Adding ordinary distillation stages alone does not overcome an azeotropic composition.
NCERT
- Chemistry XII: Solutions IndiaEnglish
§1.1, printed pp1–2: solution, solute and solvent; §1.3.1, printed pp5–6: dissolution and saturation equilibrium; §1.5.2, printed p14: azeotropic composition
- Chemistry XII: Solutions
Entry details
Permanent link to this entry ↗- Record identity
- foundation-chem-distillation
- Revision
- foundations-audit.1
- Structured reference record
- Foundational core completion