Before You Begin
Question #44351
The Question
Consider the following reaction sequence for 1-bromo-4-nitrobenzene:
\textbf{Pathway I:} Treatment with \ce{Sn / HCl} followed by basification with aqueous \ce{NaOH} yields major product .
\textbf{Pathway II:} Treatment with excess \ce{LiAlH4} in dry ether at reflux, followed by careful aqueous workup yields major product .
Identify the major products and .
Options
- A.
4-bromoaniline; Azobenzene
- B.
4-bromoaniline; Aniline
- C.
4-bromoaniline; 4,4'-dibromoazobenzene
- D.
4-bromoaniline; 4-bromoaniline
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|Reduction Selectivity (Sn/HCl vs LiAlH4)
Why This Question Is Tricky
Common Mistakes
This question tests the student's understanding of reagent chemoselectivity and the anomalous behavior of \ce{LiAlH4} with aromatic systems.
Students often blindly apply \ce{LiAlH4} as a universal \ce{-NO2} to \ce{-NH2} reducer, expecting 4-bromoaniline (Option D).
The dual trap lies in knowing that \ce{LiAlH4} converts aryl nitro compounds to azo compounds (not amines) AND that it acts as a powerful nucleophile capable of hydrogenolysis of aryl bromides, leading to complete dehalogenation.
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 |