Which compound gives a positive iodoform test?
- A. Propanal
- B. Propanone
- C. Benzaldehyde
- D. Methanal
Explanation
The test requires a methyl group attached directly to the carbonyl carbon, and propanone is the simplest methyl ketone, giving the pale yellow precipitate of triiodomethane with iodine in alkali. Ethanal is the only aldehyde that responds, since it too has that methyl group. Propanal, methanal and benzaldehyde all lack the required structure.
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