RP 10a: Exam Questions

Question 1

Solution X reacts with liquid ketones to form a crystalline solid.
This reaction can be used to identify a ketone if the crystalline solid is separated,
purified by recrystallisation, and the melting point determined.
Describe how the crystalline solid is separated and purified.

Answer 1

1. Filter the crystalline solid.
2. Dissolve the solid in hot solvent - for example, heat a test tube containing the solid and ethanol in a water bath and stir.
3. Leave the solution to crystallise.
4. Filter the solid under reduced pressure using a Buchner funnel.
5. Wash the solid with cold solvent.