Q66 · Practice questionComplex familiar4 marks
QUESTION 66 (4 marks)
Separate samples of butan-1-ol, butan-2-ol and 2-methylpropan-2-ol are heated with excess acidified potassium dichromate.
a) State the organic product for each alcohol under reflux, or state that no oxidation occurs. [3 marks]
b) Explain the behaviour of the tertiary alcohol. [1 marks]
WORKED SOLUTION
4 marksPractice marking scheme
Butanoic acid; butan-2-one; no oxidation of 2-methylpropan-2-ol under these conditions.
Primary alcohol oxidises through an aldehyde to acid; secondary alcohol gives a ketone. The tertiary carbon bearing OH has no attached H, so ordinary alcohol oxidation without C–C bond cleavage is unavailable.
- Identifies butanoic acid. [1 marks]
- Identifies butan-2-one. [1 marks]
- States no oxidation of tertiary alcohol under the specified conditions. [1 marks]
- Explains absence of H on the OH-bearing carbon. [1 marks]
Practice question aligned to the current QCAA syllabus; review the worked solution and marking criteria.
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