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Question #44356
The Question
An organic compound \textbf{X} (3-fluoro-4-nitroaniline, ) is subjected to the following sequential one-pot reaction:\n\n\textbf{Step 1:} Treated with Phenol () and \ce{NaOH} () in DMSO at .\n\textbf{Step 2:} The resulting mixture is cooled to , followed by the addition of \ce{NaNO2} () and \ce{HCl} ().\n\nAssuming complete conversion in Step 1, what is the major organic product isolated at the end of Step 2?
Options
- A.
3-phenoxy-4-nitrobenzenediazonium chloride
- B.
1,3-bis(3-phenoxy-4-nitrophenyl)triazene
- C.
4-[(3-phenoxy-4-nitrophenyl)diazenyl]phenol
- D.
3-phenoxy-4-nitrophenol
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
Nucleophilic Aromatic Substitution (SNAr)|Azo Coupling Regioselectivity|Diazotization Temperature Sensitivity
Why This Question Is Tricky
Common Mistakes
This problem tests the student's ability to track limiting reagents across a multi-step synthesis and understand the mechanistic pH-dependence of diazotization.
The 'Hidden Variable' is the residual strong base from the SNAr step.
Students typically memorize '\ce{NaNO2} + \ce{HCl} -> Diazonium salt' without considering the stoichiometric requirement of excess acid to maintain an acidic pH.
If the pH is neutral or mildly basic, the free amine acts as a nucleophile, leading to premature N-coupling (diazoamino formation) rather than the stable diazonium chloride.
Quick Facts About This Question
Question Information
| Subject | Chemistry |
| Chapter | Haloalkanes and Haloarenes - Class 12 |
| Concept | Nucleophilic Aromatic Substitution (SNAr) |
| Difficulty | 8 |
| Cognitive Load | 7 |
| Target Solve Time | 160 sec |
| Access | Free |