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Question #44385

Difficulty: 8/10 | 🟢 Free

The Question

Consider the azo coupling reactions of 3-aminophenol ( $\textbf{X}$ ) with benzenediazonium chloride under two different pH conditions at $273 - 278\text{ K}$ :

Reaction I: $\textbf{X} + \ce{PhN2+Cl-} \xrightarrow{\text{pH } 9-10} \textbf{P}$ (Major Product)

Reaction II: $\textbf{X} + \ce{PhN2+Cl-} \xrightarrow{\text{pH } 4-5} \textbf{Q}$ (Major Product)

Identify the correct IUPAC names for the major products $\textbf{P}$ and $\textbf{Q}$ .

Options

A.
$\textbf{P}$ : 3-amino-4-(phenyldiazenyl)phenol ; $\textbf{Q}$ : 5-amino-2-(phenyldiazenyl)phenol
B.
$\textbf{P}$ : 5-amino-2-(phenyldiazenyl)phenol ; $\textbf{Q}$ : 3-amino-4-(phenyldiazenyl)phenol
C.
$\textbf{P}$ : 3-amino-4-(phenyldiazenyl)phenol ; $\textbf{Q}$ : 3-amino-6-(phenyldiazenyl)phenol
D.
$\textbf{P}$ : 3-amino-6-(phenyldiazenyl)phenol ; $\textbf{Q}$ : 3-amino-4-(phenyldiazenyl)phenol

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

EAS in Phenols|Azo Coupling Regioselectivity

Why This Question Is Tricky

Common Mistakes

This question tests pH-dependent regioselectivity in Azo Coupling and competitive directing effects.

The 'hidden variable' is the dramatic increase in the +M effect of the hydroxyl group upon deprotonation to phenoxide, which flips the dominant directing group from -NH2 (in acidic medium) to -O^- (in basic medium).

Furthermore, it incorporates a nomenclature trap: students who correctly identify the coupling position in acidic medium but fail to renumber the ring for the lowest locant set will incorrectly choose '3-amino-6-(phenyldiazenyl)phenol'.

Quick Facts About This Question

Question Information

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