Chemistry Hydrocarbons PMC 2021
PMDC Verified Question 17 of 65
Benzene does not show
A
Addition reactions
B
Substitution receptions
C
Oxidation reactions
D
Elimination reactions
Tap any option to test your recall and reveal the step-by-step Propolis autopsy.

Propolis Cognitive Error Autopsy

Official Correct Choice:
Option D: Elimination reactions
Concept:

Benzene undergoes substitution readily to preserve its resonance stability. It can undergo harsh addition and oxidation, but lacks a mechanism for basic elimination.

Solution:

  • Elimination reactions require saturated \( \text{sp}^3 \) carbons with adjacent leaving groups (like alkyl halides) to form a new pi bond.


  • Benzene is already fully unsaturated and aromatic. Attempting to "eliminate" from it to create a triple bond in a six-membered ring would create unbearable ring strain (though transient arynes exist, they are extreme intermediates, not standard reactions).


  • Therefore, chemically speaking in the context of standard pathways, benzene does not show elimination.


Why other options are incorrect:

  • Benzene easily undergoes electrophilic Substitution.


  • Under extreme conditions, it can undergo Addition (with \( \text{Cl}_2 \) + UV, or \( \text{H}_2 \) + Ni) and Oxidation (with \( \text{V}_2\text{O}_5 \)).

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