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JEE Main · 2025 · 03 Apr 2025 · Shift 1 · Aldehydes Ketones and Carboxylic Acids

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Number of molecules from below which cannot give ioddoform reaction is :
Ethanol, Isopropyl alcohol, Bromoacetone, 2-Butanol, 2-Butanone, Butanal, 2-Pentanone, 3-Pentanone, Pentanal and 3-Pentanol
  1. (A)5
  2. (B)4✓ Correct
  3. (C)3
  4. (D)2

Answer: (B)

Solution

The iodoform test is positive for a methyl ketone, , or an alcohol oxidisable to one, . Ethanol, isopropyl alcohol, 2-butanol, 2-butanone, 2-pentanone and bromoacetone each carry such a grouping and respond. Butanal and pentanal are straight-chain aldehydes, 3-pentanone is a ketone without a methyl next to the carbonyl, and 3-pentanol is a secondary alcohol with no adjacent methyl, so none of these four responds. The number of compounds that cannot give the iodoform reaction is .

JEE Main · 2025 · 03 Apr 2025 · Shift 1 · Single correct option

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