JEE Main · 2006 · 30 Apr 2006 · Offline · Aldehydes Ketones and Carboxylic Acids

Among the following the one that gives positive iodoform test upon reaction with

I_{2}

and NaOH is

(A) $CH_{3} CH_{2} CH (OH) CH_{2} CH_{3}$
(B) $C_{6} H_{5} CH_{2} CH_{2} OH$
(C)(see structure)
(D) $PhCHOHCH_{3}$ ✓ Correct

Answer: (D)

Solution

A positive iodoform test needs either a methyl ketone,

C H_{3} CO -

, or a secondary alcohol of the form

C H_{3} CH (OH) -

that iodine and alkali can first oxidise to such a ketone. Among the choices, 1-phenylethanol,

PhCH (OH) C H_{3}

, carries exactly this

C H_{3} CH (OH) -

unit and so delivers the yellow iodoform, whereas the others have no methyl group next to the carbinol or carbonyl carbon. The compound giving the positive test is therefore

PhCH (OH) C H_{3}

JEE Main · 2006 · 30 Apr 2006 · Offline · Single correct option

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JEE Main · 2006 · 30 Apr 2006 · Offline · Aldehydes Ketones and Carboxylic Acids

Solution

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