A Levels Chemistry (9701)•9701/12/M/J/22

Explanation
Iodoform test identifies methyl ketones or oxidizable alcohols
Steps:
- Identify the iodoform test: yellow CHI3 precipitate from CH3COR or CH3CH(OH)R with alkaline I2/NaI.
- Analyze each reaction's product for the required structural motif.
- Check A: 2-chloropropane + dilute NaOH(aq) → 2-propanol (CH3CH(OH)CH3), matches CH3CH(OH)-.
- Eliminate others as products lack the motif.
Why A is correct:
- 2-Propanol oxidizes to acetone (CH3COCH3), a methyl ketone that reacts with alkaline I2 to form CHI3 precipitate per iodoform reaction.
Why the others are wrong:
- B: Ethanol oxidizes to CH3COOH (reflux ensures full oxidation), which lacks CH3CO- or CH3CH(OH)- group.
- C: Methyl ethanoate hydrolyzes to CH3OH and CH3COOH, neither undergoes iodoform test.
- D: Propanal reduces to CH3CH2CH2OH, a primary alcohol not oxidizable to methyl ketone/aldehyde.
Final answer: A
Topic: Hydroxy compounds
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