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Aromatic chemistry (A-level only) study guide
Study Aromatic chemistry (A-level only) with curriculum-aligned Study Guide resources, practice links, and exam-focused support.
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Aromatic chemistry (A-level only)
AqaA LevelChemistryOrganic chemistry
Study guide overview
Aromatic Chemistry Study Guide
This guide covers the essential concepts and reactions of aromatic compounds, focusing on benzene.
Aromatic Chemistry Study Guide
Key Concepts
- Delocalised Electrons: In benzene, the p-orbitals overlap to form a cloud of electrons above and below the plane of the ring, contributing to its stability.
- Stability Comparison: Benzene is more stable than cyclohexatriene due to the resonance energy associated with its delocalised electrons.
Important Reactions
1. Nitration of Benzene
- Reaction: Benzene + HNO₃ (in H₂SO₄) → Nitrobenzene + H₂O
- Mechanism: Formation of the nitronium ion (NO₂⁺) which acts as the electrophile.
2. Friedel-Crafts Alkylation
- Reaction: Benzene + R-X (alkyl halide) → Alkylbenzene + HX
- Mechanism: Formation of a carbocation or complex with AlCl₃ as a catalyst.
3. Friedel-Crafts Acylation
- Reaction: Benzene + RCOCl (acyl chloride) → Acylbenzene + HCl
- Mechanism: Similar to alkylation but introduces a carbonyl group.
Tips for Mastery
- Practice drawing mechanisms to visualize electron movement.
- Compare and contrast the stability of benzene with other cyclic compounds.
- Familiarize yourself with the conditions required for each reaction.
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