Class 11 Chemistry Chapter 9 Hydrocarbons – Revision Notes

Quick revision notes for Class 11 Chemistry Chapter 9 (Hydrocarbons). These Class 11 Chemistry Chapter 9 notes are ideal for quick revision just before exams.

Classification

• Alkanes C_nH_2n+2 (saturated); Alkenes C_nH_2n; Alkynes C_nH_2n−2; Arenes (benzene ring).

Key Reactions

• Alkanes: substitution (free radical), Wurtz reaction.
• Alkenes/Alkynes: electrophilic addition; Markovnikov’s rule.
• Arenes: electrophilic substitution (nitration, halogenation, sulphonation, Friedel-Crafts).

Directive Effects

• Ortho/para-directing: -OH, -NH₂, -CH₃ (activating).
• Meta-directing: -NO₂, -COOH (deactivating).

One-Line Summary

Hydrocarbons range from saturated alkanes to unsaturated alkenes/alkynes and aromatic arenes, each with characteristic reaction patterns (substitution, addition, or aromatic substitution) governed by their bonding and structure.

Written by Satish

NCERTBooks.org is an independent educational resource run by a small team focused on making official NCERT textbooks easy to find, read, and download for students, parents, and teachers across India. We are not affiliated with NCERT or the Ministry of Education -- we organise publicly available NCERT content by class and subject, verify links against official sources, and build tools (like our in-browser reader) that make studying more convenient. Every guide we publish is written and reviewed by our team based on the actual NCERT curriculum and syllabus.