3.2.9—Oxidation of organic functional groups
- Syllabus
- First assessment 2025
- Objective
- 3.2.9
- Level
- HL
Oxidation of Alcohols
A primary alcohol oxidizes to an aldehyde and then a carboxylic acid; a secondary alcohol oxidizes to a ketone. Reflux supports further oxidation to the acid, while distillation can remove an aldehyde.
In a primary-alcohol experiment, distil the aldehyde as it forms to limit further oxidation; heat under reflux when the carboxylic acid is required. Tertiary alcohols lack the required hydrogen on the carbon bearing –OH and are not oxidized in the same way.
Choosing Alcohol-Oxidation Products
Assessment in practice
Representative question
Question 1
[Maximum number: 2]
Deduce the organic products when butan-1-ol and butan-2-ol are separately heated under reflux with acidified potassium dichromate(VI).
Butan-1-ol:
Butan-2-ol:
butanoic acid
butanone
Marking guidance:
Accept butan-2-one / 2-butanone.
Accept correct structures
Electron Transfer Reactions Summary
Retrieve the route: assign oxidation states, balance half-equations, predict displacement, label cells, trace electrons and ions, follow organic redox pathways, calculate potentials and choose electrolysis products.
Check electron loss/gain, anode/cathode versus polarity, spontaneous sign, salt-bridge direction, ions present, organic functional-group direction and object-cathode placement.