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Question #44489

Difficulty: 8/10 | 🟢 Free

The Question

Consider the following reaction sequence starting from $m$ -xylene:

$m$ -Xylene $\xrightarrow{t-BuCl, \text{ anhydrous } AlCl_3, 298\text{ K}}$ $\mathbf{P}$ (Major product)
$\mathbf{P} \xrightarrow[\text{2. } H_3O^+]{\text{1. } KMnO_4, KOH, \Delta}$ $\mathbf{Q}$
$\mathbf{Q} \xrightarrow[\text{2. excess } NH_3]{\text{1. } SOCl_2, \Delta}$ $\mathbf{R}$
$\mathbf{R} \xrightarrow{Br_2, NaOH, \Delta}$ $\mathbf{S}$

Identify the final product $\mathbf{S}$ .

Options

A.
5-tert-butylbenzene-1,3-diamine
B.
4-tert-butylbenzene-1,3-diamine
C.
2-tert-butylbenzene-1,3-diamine
D.
Benzene-1,3,5-triamine

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 Orientation|Steric Hindrance (B-Strain)|Electrophilic Substitution Control

Why This Question Is Tricky

Common Mistakes

This problem tests the critical exception where steric control completely overrides electronic control in Electrophilic Aromatic Substitution.

Students typically apply the standard rule that alkyl groups are ortho/para directing, which would incorrectly predict substitution at position 4.

However, the massive steric bulk of the tert-butyl electrophile makes the electronically favored ortho-position inaccessible, forcing substitution to the meta-position (position 5).

Additionally, it tests a hidden variable in side-chain oxidation: the absolute requirement of a benzylic hydrogen, trapping students who might incorrectly assume the tert-butyl group is also oxidized to a carboxyl group.

Quick Facts About This Question

Question Information

Subject	Chemistry
Chapter	Hydrocarbons - Class 11 Part 2
Concept	Electrophilic Substitution Orientation
Difficulty	8
Cognitive Load	7
Target Solve Time	160 sec
Access	Free