A compound X, C4H8O, is reduced by LiAlH4 (then H3O+) to Y. Y gives a yellow precipitate with I2/NaOH and gives turbidity with the Lucas reagent only after about five minutes at room temperature. X is

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JEE Advanced levelSingle correct optionDifficulty 3 of 3ap180

A compound X, $C X_{4} H X_{8} O$ , is reduced by $LiAlH X_{4}$ (then $H X_{3} O X^{+}$ ) to Y. Y gives a yellow precipitate with $I X_{2}$ / $NaOH$ and gives turbidity with the Lucas reagent only after about five minutes at room temperature. X is

Abutanal
B2-methylpropanal
Cbut-3-en-1-ol
Dbutan-2-one

Answer: D

The Lucas delay of about five minutes marks a secondary alcohol, and the iodoform test marks

CH X_{3} CH (OH) - R

. So Y is butan-2-ol,

CH X_{3} CH (OH) CH X_{2} CH X_{3}

. Reduction of the ketone

CH X_{3} COCH X_{2} CH X_{3}

, butan-2-one (C4H8O), gives Y. Butanal would give a primary alcohol and 2-methylpropanal gives a primary alcohol too, while but-3-en-1-ol is not reduced to a secondary alcohol.

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A compound X, CX4​HX8​O, is reduced by LiAlHX4​ (then HX3​OX+) to Y. Y gives a yellow precipitate with IX2​/NaOH and gives turbidity with the Lucas reagent only after about five minutes at room temperature. X is

Answer: D

More questions on Preparation of alcohols including from carbonyls and Grignard

A compound X, $C X_{4} H X_{8} O$ , is reduced by $LiAlH X_{4}$ (then $H X_{3} O X^{+}$ ) to Y. Y gives a yellow precipitate with $I X_{2}$ / $NaOH$ and gives turbidity with the Lucas reagent only after about five minutes at room temperature. X is