Which compound produces a bright yellow precipitate of Iodoform (CHI3) when treated with I2 and NaOH solution?
Answer and explanation
Correct answer: A. Ethanol (CH3-CH2-OH)
- Step 1: The iodoform test is positive for compounds containing a CH3-C=O group or a CH3-CH(OH)- group oxidizable to it. Step 2. Ethanol is oxidized by iodine to acetaldehyde (CH3-CHO), which has the methyl carbonyl group and yields yellow CHI3 precipitate. Answer: Ethanol (CH3-CH2-OH). Why not the others: Methanol lacks methyl carbonyl; 1-Propanol oxidizes to propanal (CH3-CH2-CHO) lacking CH3-C=O; Benzaldehyde has no methyl group.
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