Chemistry Hydrocarbons MDCAT 2019
PMDC Verified Question 38 of 65
Which derivative of benzene shows maximum reactivity in electrophilic substitution reactions?
A
Benzaldehyde
B
Benzoic acid
C
Methyl benzene
D
Nitrobenzene
Tap any option to test your recall and reveal the step-by-step Propolis autopsy.

Propolis Cognitive Error Autopsy

Official Correct Choice:
Option C: Methyl benzene
Concept:

Ring reactivity is dictated by attached functional groups. Electron-donating groups (EDGs) activate the ring, while electron-withdrawing groups (EWGs) deactivate it.

Solution:

  • Methyl benzene (Toluene): The methyl group (\( -\text{CH}_3 \)) pushes electron density into the ring via the inductive effect and hyperconjugation. This makes the ring more electron-rich and highly reactive to electrophiles.


  • Benzaldehyde, Benzoic acid, and Nitrobenzene: All contain potent EWGs (\( -\text{CHO} \), \( -\text{COOH} \), and \( -\text{NO}_2 \)) that drain electrons from the pi system through resonance, strongly deactivating the ring.


  • Therefore, methyl benzene is the only activated ring listed, thus having maximum reactivity.


Why other options are incorrect:

  • They all contain deactivating meta-directing groups that significantly slow down electrophilic substitution compared to pure benzene.

Quality & Fidelity Assurance: Every question on BeambePrep is rigorously curated against the official PMDC syllabus with zero filler, zero out-of-syllabus content, and zero typos. When an authentic past paper originally contained a historical mistake or ambiguity from the examining board (such as UHS or NUMS), BeambePrep faithfully reflects the original paper while detailing the nuance and scientific consensus in the autopsy above.

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