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JEE Main · 2026 · 05 Apr 2026 · Shift 2 · Aldehydes Ketones and Carboxylic Acids

Given below are two statements :

Statement-I : The condensation reaction between CH₃-CH=O and (see structure) under optimum pH will produce (see structure)

Statement-II : The molecule, (see structure) will generate Ph-CH=O in the presence of dilute acid.

In the light of the above statements, choose the correct answer from the options given below :

(A)Both Statement-I and Statement-II are true.
(B)Both Statement-I and Statement-II are false.
(C)Statement-I is true but Statement-II is false.
(D)Statement-I is false but Statement-II is true.✓ Correct

Answer: (D)

Solution

Semicarbazide,

H_{2} N - NH - CO - N H_{2}

, condenses through the terminal

- N H_{2}

of its hydrazine part, so acetaldehyde gives the semicarbazone

C H_{3} CH = N - NH - CO - N H_{2}

; the structure drawn,

C H_{3} CH = N - CO - NH - N H_{2}

, has the wrong connectivity, so Statement-I is false. The second molecule,

Ph - CH (OH) (OC H_{3})

, is a hemiacetal of benzaldehyde, and hemiacetals are cleaved by dilute acid back to the carbonyl compound, releasing

Ph - CHO

, so Statement-II is true. Statement-I is false but Statement-II is true.

JEE Main · 2026 · 05 Apr 2026 · Shift 2 · Single correct option

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