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Question #44349

Difficulty: 8/10 | 🟢 Free

The Question

Consider the following reaction sequence:

$\text{Naphthalen-2-ol} \xrightarrow[\text{120 }^\circ\text{C, 4-7 atm}]{\text{1. } \ce{NaOH, CO2} \text{ 2. } \ce{H3O+}} \textbf{X} \text{ (Major Product)}$

$\textbf{X} \xrightarrow[\text{pH = 9-10, 0-5 }^\circ\text{C}]{\ce{Ph-N2+ Cl-}} \textbf{Y} \text{ (Major Product)}$

Identify \textbf{X} and \textbf{Y}.

Options

A.
$\textbf{X}$ = 2-Hydroxynaphthalene-1-carboxylic acid; $\textbf{Y}$ = 1-(Phenyldiazenyl)naphthalen-2-ol
B.
$\textbf{X}$ = 2-Hydroxynaphthalene-1-carboxylic acid; $\textbf{Y}$ = 6-(Phenyldiazenyl)-2-hydroxynaphthalene-1-carboxylic acid
C.
$\textbf{X}$ = 3-Hydroxynaphthalene-2-carboxylic acid; $\textbf{Y}$ = 1-(Phenyldiazenyl)-3-hydroxynaphthalene-2-carboxylic acid
D.
$\textbf{X}$ = 3-Hydroxynaphthalene-2-carboxylic acid; $\textbf{Y}$ = 4-(Phenyldiazenyl)-3-hydroxynaphthalene-2-carboxylic acid

Check Your Answer

Correct Answer

Step-by-Step Solution

Explanation

How the Examiner Thinks

Mechanism_Trap

Don't get tricked by the process! Learn the mechanical traps used in competitive exam questions.

Concepts Behind This Question

Electrophilic Substitution Activation/Deactivation|Azo Coupling Regioselectivity

Why This Question Is Tricky

Common Mistakes

This question tests two critical exceptions in electrophilic aromatic substitution.

First, the temperature-dependent regioselectivity of the Kolbe-Schmitt reaction on 2-naphthol (Kinetic vs Thermodynamic control).

Second, the 'hidden' ipso-substitution in azo coupling.

Students typically assume that if the most reactive position (C1) is blocked by a substituent, the electrophile will attack the next available position (e.g., C6).

However, because the carboxyl group is an excellent leaving group (as $\ce{CO2}$ ) and the C1 position is overwhelmingly activated, the diazonium ion attacks the ipso position, displacing the carboxyl group entirely.

Quick Facts About This Question

Question Information

Subject	Chemistry
Chapter	Haloalkanes and Haloarenes - Class 12
Concept	Electrophilic Substitution Activation/Deactivation
Difficulty	8
Cognitive Load	7
Target Solve Time	160 sec
Access	Free