Reflux vs Distillation Virtual Lab: Oxidation of Ethanol
Assemble a reflux or a distillation apparatus from flask, still head, thermometer, Liebig condenser and receiver, then oxidise ethanol with acidified potassium dichromate(VI). Distilling straight away gives ethanal; heating under reflux gives ethanoic acid. Common mistakes — a sealed system, a misplaced thermometer, cooling water the wrong way round, no anti-bumping granules — are checked and their consequences shown.
About this simulation
- What
- An interactive Chemistry simulation of Reflux vs Distillation Virtual Lab: Oxidation of Ethanol.
- Who
- Designed for AP, IB, and A‑Level Chemistry students.
- How
- Runs in any modern browser — drag, adjust, and explore in real time.
Updated 2026-10-11
Key Concepts
The apparatus decides the product
Ethanal boils at 20 °C. Distilling as it forms removes it before it can be oxidised further; heating under reflux returns it to the flask until it becomes ethanoic acid.
Heating under reflux
A vertical condenser, open at the top, condenses the vapour and returns it to the flask, so volatile reactants and products can be heated for a long time without boiling away.
Simple distillation
The thermometer bulb sits level with the side arm so it reads the temperature of the vapour entering the condenser; the receiver is open, and cooled in ice for a volatile product.
Cooling water in at the bottom
Water enters the lower end of the condenser and leaves at the upper end, so the jacket stays completely full and the whole length of the inner tube is cooled.
What This Reflux & Distillation Lab Teaches
Oxidising ethanol with acidified potassium dichromate(VI) can give two products. Ethanal, the aldehyde, boils at 20 °C — below the temperature of the reaction mixture — so if the apparatus lets it escape as it forms, it is collected before it can be oxidised further. Under reflux the vapour is condensed and returned to the flask, and with the oxidant in excess the ethanal is oxidised all the way to ethanoic acid. This is AQA A-level topic 3.3.5.2 and Required Practical 5.
In this lab you build the apparatus from individual pieces. The same Liebig condenser stands vertically on the flask for reflux, or slopes down from the still head's side arm for distillation. You decide where the thermometer bulb sits, which end the cooling water enters, whether the receiver is cooled and whether anti-bumping granules are added — and the run shows what each choice does.
Make the acid in two stages: heat under reflux, then rebuild the apparatus for distillation without emptying the flask and collect the acid as it distils. Try a reflux when you want the aldehyde, or distil straight away when you want the acid, to see why the apparatus matters.
Frequently Asked Questions
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