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Question #44390

Difficulty: 8/10 | 🟢 Free

The Question

Consider the following two independent reaction sequences:

\textbf{Sequence 1:} 3-Methoxyphenol is treated with aqueous \ce{NaOH}. The mixture is evaporated to dryness, and the resulting solid is heated at $125^\circ\mathrm{C}$ under $5\text{ atm}$ of \ce{CO2} gas. Subsequent acidification with dilute \ce{HCl} yields \textbf{X} as the major product.

\textbf{Sequence 2:} 4-Nitrophenol is treated with aqueous \ce{NaOH}. The mixture is evaporated to dryness, and the resulting solid is heated at $125^\circ\mathrm{C}$ under $5\text{ atm}$ of \ce{CO2} gas. Subsequent acidification with dilute \ce{HCl} yields \textbf{Y} as the major product.

Identify the major products \textbf{X} and \textbf{Y}.

Options

A.
\textbf{X} = 2-Hydroxy-4-methoxybenzoic acid; \textbf{Y} = 4-Nitrophenol
B.
\textbf{X} = 2-Hydroxy-4-methoxybenzoic acid; \textbf{Y} = 2-Hydroxy-5-nitrobenzoic acid
C.
\textbf{X} = 2-Hydroxy-6-methoxybenzoic acid; \textbf{Y} = 2-Hydroxy-5-nitrobenzoic acid
D.
\textbf{X} = 4-Hydroxy-2-methoxybenzoic acid; \textbf{Y} = 4-Nitrophenol

Check Your Answer

Correct Answer

Step-by-Step Solution

Explanation

How the Examiner Thinks

Exception_Exposure

Learn to identify edge cases and boundary exceptions that JEE examiners hide in math problems.

Concepts Behind This Question

Kolbe-Schmitt Reaction Mechanism|Phenol Acidity vs. Substituents

Why This Question Is Tricky

Common Mistakes

The question tests the critical distinction between thermodynamic acidity and kinetic nucleophilicity in Electrophilic Aromatic Substitution (EAS).

A common student trap is assuming that because strong electron-withdrawing groups (EWGs) like \ce{-NO2} increase phenol acidity (facilitating phenoxide formation), they should enhance Kolbe-Schmitt reactivity.

In reality, the $-M$ and $-I$ effects of the \ce{-NO2} group drastically reduce the nucleophilicity of the aromatic ring, making the rate-determining attack on \ce{CO2} kinetically unfeasible, thus halting the reaction.

Additionally, the problem tests regioselectivity in 3-methoxyphenol, requiring the evaluation of synergistic $+M$ electronic effects and steric hindrance to correctly identify the major ortho-isomer.

Quick Facts About This Question

Question Information

Subject	Chemistry
Chapter	Alcohols, Phenols, and Ethers - Class 12
Concept	Kolbe-Schmitt Reaction Mechanism
Difficulty	8
Cognitive Load	7
Target Solve Time	160 sec
Access	Free