NEET 2023 Phase 1 · ChemistryTollens testPrevious Year Question

Identify the major product obtained when 2-acetylbenzaldehyde (an ortho-disubstituted benzene bearing $- CO - CH X_{3}$ and $- CHO$ ) is treated with $2 [Ag (NH X_{3}) X_{2}] X^{+}$ and $3 OH X^{-}$ on heating.

Answer: (C) (C) Benzene ring bearing $- CO - CH X_{3}$ (intact) and $- COO -$ (2-acetylbenzoate). \textbf{Answer:} (C) Benzene ring bearing $- CO - CH X_{3}$ (intact) and $- COO -$ (2-acetylbenzoate) \textbf{Solution:} Tollens' reagent $[Ag (NH X_{3}) X_{2}] X^{+}$ is a mild oxidant that oxidises aldehydes to carboxylate ions under basic conditions while depositing a silver mirror, but it does not oxidise ketones.

A.(A) Benzene ring bearing $- CH (OH) CH X_{3}$ and $- CH X_{2} OH$
B.(B) Benzene ring bearing $- CO - CH X_{3}$ (intact) and $- CH X_{2} OH$
C.(C) Benzene ring bearing $- CO - CH X_{3}$ (intact) and $- COO -$ (2-acetylbenzoate)✓
D.(D) Benzene ring bearing $- CH (OH) CH X_{3}$ and $- COO -$

Correct Answer

Solution & Explanation

\textbf{Answer:} (C) Benzene ring bearing $- CO - CH X_{3}$ (intact) and $- COO -$ (2-acetylbenzoate) \textbf{Solution:} Tollens' reagent $[Ag (NH X_{3}) X_{2}] X^{+}$ is a mild oxidant that oxidises aldehydes to carboxylate ions under basic conditions while depositing a silver mirror, but it does not oxidise ketones. Therefore only the $- CHO$ group is oxidised to $- COO -$ , while the acetyl $- CO - CH X_{3}$ group stays intact, giving the 2-acetylbenzoate ion.

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Identify the major product obtained when 2-acetylbenzaldehyde (an ortho-disubstituted benzene bearing −CO−CHX3​ and −CHO) is treated with 2[Ag(NHX3​)X2​]X+ and 3OHX− on heating.

Solution & Explanation

More NEET PYQ solutions

Identify the major product obtained when 2-acetylbenzaldehyde (an ortho-disubstituted benzene bearing $- CO - CH X_{3}$ and $- CHO$ ) is treated with $2 [Ag (NH X_{3}) X_{2}] X^{+}$ and $3 OH X^{-}$ on heating.