Revision Notes: Class 10 Science Chapter 4 Carbon and its Compounds

A fast, one-glance recap of Class 10 Science Chapter 4 (Carbon and its Compounds) — for full worked explanations, see the Solutions. These Class 10 Science Chapter 4 notes are ideal for quick revision just before exams.

Last Updated: July 21, 2026

Why This Chapter Matters

Carbon and its Compounds is one of the standard chapters in the CBSE/NCERT Class 10 Science syllabus and questions from it appear regularly in board exams, in formats ranging from 1-mark objective questions to longer 3-5 mark descriptive or numerical questions. Because the concepts here often build on earlier chapters (and feed into later ones), a solid grip on this chapter also makes the rest of the Science syllabus easier to follow.

Revision Notes: Carbon and its Compounds

• Covalent bonding: carbon has 4 valence electrons, shares electrons (rather than gaining/losing 4) to complete its octet, forming strong covalent bonds
• Allotropes of carbon: diamond (rigid tetrahedral network, hardest natural substance), graphite (hexagonal layers, soft, conducts electricity), fullerenes
• Saturated hydrocarbons (alkanes): C–C single bonds only, general formula CₙH₂ₙ⁺₂
• Unsaturated hydrocarbons: alkenes (C=C, CₙH₂ₙ), alkynes (C≡C, CₙH₂ₙ−₂)
• Homologous series: same general formula, similar chemical properties, each member differs by –CH₂– (14u)
• Functional groups: –OH (alcohol), –COOH (carboxylic acid), –CHO (aldehyde), >C=O (ketone), –X (halide)
• Test for unsaturation: bromine water decolourised = unsaturated; no change = saturated
• Combustion: complete (blue flame, CO₂+H₂O) vs incomplete (yellow sooty flame, CO + soot)
• Oxidation: alcohols → carboxylic acids (using alkaline KMnO₄ or acidified K₂Cr₂O₉)
• Addition reaction (hydrogenation): unsaturated + H₂ (Ni catalyst) → saturated (vegetable oil → vanaspati ghee)
• Substitution reaction: saturated hydrocarbons + halogen (sunlight) → halogen replaces H atoms one by one
• Esterification: alcohol + carboxylic acid (acid catalyst) → ester (sweet smell) + water
• Soap: sodium/potassium salt of a long-chain fatty acid; hydrophilic head + hydrophobic tail; forms micelles to trap dirt
• Hard water + soap → scum (insoluble Ca/Mg salts of fatty acids); detergents work even in hard water

Related: Solutions | Extra Questions | Revision Notes | Formulas Handbook | Class 10 Science Book

How to Use These Notes

These revision notes are meant for quick recall in the last few days before an exam or unit test — they are not a substitute for first reading the full chapter and working through examples in the NCERT textbook. A good routine is: read the chapter once, solve the in-text and end-of-chapter questions using the linked Solutions, then come back to this page a day or two before the exam to refresh the key definitions and formulas without re-reading the whole chapter.

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.