Fundamentholfundamenthol

JEE Advanced 2022 Paper 2, Chemistry Section 2 Q5: Properties and Important Reactions of Aldehydes & Ketones

JEE Advanced2022Paper 2Chemistry Section 2
Q.

Considering the following reaction sequence, the correct statement(s) is(are)

  1. A

    Compounds P and Q are carboxylic acids.

  2. B

    Compound S decolorizes bromine water.

  3. C

    Compounds P and S react with hydroxylamine to give the corresponding oximes.

  4. D

    Compound R reacts with dialkylcadmium to give the corresponding tertiary alcohol.

Solution

P is 4-oxo-4-phenylbutanoic acid (a keto-acid); Q is 4-phenylbutanoic acid; R is the corresponding acyl chloride; S is -tetralone (a cyclic aryl ketone).

(A) Both P and Q bear a COOH group; both are carboxylic acids. Correct.

(B) S is a saturated cyclic ketone fused to a benzene ring; it has no isolable C=C double bond outside the aromatic ring (aromatic rings do not decolorize Br water under normal conditions). Incorrect.

(C) Both P (contains a ketone CO) and S (cyclic ketone) react with NHOH at the carbonyl carbon to give oximes. Correct.

(D) Dialkylcadmium R'Cd is a mild nucleophile that converts acyl chlorides to ketones (it stops at the ketone stage and does not add twice). Hence R + R'Cd gives a ketone, not a tertiary alcohol. Incorrect.

(A), (C).

Concept behind this question

Properties and Important Reactions of Aldehydes & Ketones Notes, formulas and examples →

More previous year questions on Properties and Important Reactions of Aldehydes & Ketones

Practice more Chemistry Section 2

Concept-wise practice with instant solutions on Fundamenthol.

Start practicing →