# A student has carried out a reaction to produce an organic liquid product. The crude product contains unreacted starting materials, water, and traces of acid catalyst. Describe how the student could purify and dry the organic liquid to obtain a pure, dry sample.

> WJEC A-Level Chemistry (Wales) — 4.8 Organic synthesis and analysis · Describe · 5 marks

> In organic synthesis, the crude product mixture must be processed after the reaction to remove impurities before a pure sample can be collected.

## Mark scheme (5 marks)

1. Use a separating funnel to wash the crude product / shake the crude product with water in a separating funnel to remove water-soluble impurities (unreacted starting materials and acid catalyst)
2. Run off / separate the aqueous layer from the organic layer using the separating funnel tap
3. Add a drying agent (e.g. anhydrous calcium chloride / anhydrous magnesium sulfate / anhydrous sodium sulfate) to the organic layer to remove traces of water
4. Filter / decant the dried organic liquid to remove the solid drying agent
5. Distil the organic liquid and collect the fraction at the correct / expected boiling point to obtain the pure product

## Related

- [Revision notes for WJEC A-Level Chemistry (Wales)](https://www.gradenine.co.uk/learn)
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Source: [GradeNine](https://www.gradenine.co.uk/q/a-student-has-carried-out-a-a3bcf2e4) · Published by Druglandscape Ltd.