⚗️ CBSE · Class 10 · Science · Chapter 4

Carbon and its
Compounds

Complete chapter resources for CBSE Class 10 Science — topic breakdown, key concepts, sample questions, previous year board questions, and instant AI question paper generation.

5Topics
6–8Board marks
8Sample questions
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Key Concepts — Chapter 4
  • Covalent bond: Shared pair of electrons between non-metals
  • Alkanes (CnH2n+2): Saturated · only C–C single bonds
  • Alkenes (CnH2n): Unsaturated · one C=C double bond
  • Alkynes (CnH2n−2): Unsaturated · one C≡C triple bond
  • Combustion: CₓHᵧ + O₂ → CO₂ + H₂O + heat
  • Saponification: Fat + NaOH → soap + glycerol
Chapter Overview

What this chapter covers

Carbon is a unique element capable of forming an enormous variety of compounds due to two special properties — catenation (the ability to bond with other carbon atoms to form long chains, branches, and rings) and tetravalency (four valence electrons that can form four covalent bonds). Chapter 4 begins by explaining why carbon forms covalent bonds rather than ionic bonds and how this gives rise to millions of organic compounds that are central to life, fuel, and materials.

The chapter introduces key structural families: saturated hydrocarbons (alkanes) that undergo substitution reactions, and unsaturated hydrocarbons (alkenes, alkynes) that undergo addition reactions. Students learn about functional groups — hydroxyl (–OH), aldehyde (–CHO), ketone (C=O), carboxyl (–COOH), halide (–X) — that define the chemical behaviour of a compound, and about homologous series where members share a general formula and change gradually in physical properties while retaining the same chemical properties.

Board questions in this chapter regularly cover IUPAC naming of simple compounds, identifying functional groups from structural formulas, explaining why soaps and detergents cleanse, and comparing the properties of ethanol and ethanoic acid. The chapter also covers important industrial and daily-life applications such as the combustion of fuels, the preparation of soap by saponification, and the difference between soaps (work poorly in hard water) and synthetic detergents (work in hard water).

Topics

What's inside Chapter 4

As per NCERT Class 10 Science (CBSE syllabus)

Topic 1
Bonding in Carbon — Covalent Bonds & Allotropes
Why carbon forms covalent bonds. Tetravalency and catenation. Allotropes of carbon: diamond (hard, non-conductor), graphite (soft, conductor), fullerene. Electron dot structures of simple molecules.
Topic 2
Hydrocarbons — Saturated & Unsaturated
Alkanes (CₙH₂ₙ₊₂), alkenes (CₙH₂ₙ), alkynes (CₙH₂ₙ₋₂). Structural formulas of methane, ethane, ethene, ethyne. Substitution vs addition reactions. Reaction with halogens and hydrogen.
Topic 3
Functional Groups, Homologous Series & Nomenclature
Identifying and naming functional groups: –OH, –CHO, –COOH, C=O, –X. Properties of a homologous series. IUPAC naming rules for compounds with 1–4 carbons. Isomers and structural variation.
Topic 4
Chemical Properties of Carbon Compounds
Combustion (complete and incomplete), oxidation reactions, addition reactions, substitution reactions. Properties and uses of ethanol (alcohol) and ethanoic acid (acetic acid). Reactions of ethanol with sodium and ethanoic acid.
Topic 5
Soaps, Detergents & Cleansing Action
Saponification: fat + NaOH → soap + glycerol. Structure of soap molecules (hydrophilic head + hydrophobic tail). Micelle formation and cleansing action. Why soaps fail in hard water; how synthetic detergents overcome this.
Connections

How this chapter fits in

Useful for setting question difficulty and cross-chapter papers.

Builds on
Ch 3 · Metals and Non-Metals
Ionic vs covalent bonding, valence electrons, electron dot structures
Class 9 · Atoms & Molecules
Atomic structure, valency, and molecular formula writing
Chapter 4 Carbon & its
Compounds
Leads to
Class 11 · Organic Chemistry
Hybridisation, reaction mechanisms, functional group conversions
Class 11 · Biomolecules
Carbohydrates, proteins, fats — all built on carbon frameworks
Board Blueprint

Marks & question-type breakdown

Typical pattern based on CBSE Class 10 Science board papers from the last five years.

Question type Marks Typical count What's usually tested
MCQ / Objective 1 1–2 Identify functional group, name of compound, or type of reaction
Very Short Answer 2 1 Write structural formula, explain catenation, or distinguish soap vs detergent
Short Answer 3 1 Homologous series properties, IUPAC naming, or reaction equations
Long Answer / Application 4–5 1 Cleansing action of soaps, properties of ethanol and ethanoic acid, or diagram-based
Total (approximate) 6–8 4–5 Weightage varies across paper sets and years
Sample Questions

8 sample questions — generated by MarksZen AI

Aligned to CBSE Class 10 Science Chapter 4. Covers all question types across Easy, Medium, and Hard difficulty.

Q1 Easy 1 mark MCQ
Which of the following is a saturated hydrocarbon? (a) Ethene (b) Ethyne (c) Ethane (d) Benzene
Q2 Easy 2 marks Short Answer
What is catenation? Name the property of carbon that allows it to form long chains, branches, and rings.
Q3 Medium 2 marks Short Answer
Draw the electron dot (Lewis) structure of ethene (C₂H₄). What type of bond exists between the two carbon atoms? What type of reaction does ethene undergo with bromine water?
Q4 Medium 3 marks Short Answer
What is a homologous series? List any three characteristics of a homologous series and write the first four members of the alkane series with their molecular formulas.
Q5 Medium 3 marks Short Answer
Give the IUPAC names of the following compounds: (i) CH₃–OH (ii) CH₃–CHO (iii) CH₃–CH₂–COOH Also identify the functional group present in each compound.
Q6 Hard 4 marks Short Answer
Compare the properties of ethanol and ethanoic acid under the following headings: (i) Physical state at room temperature (ii) Reaction with sodium metal (iii) Effect on litmus paper (iv) Reaction with each other (write the balanced chemical equation for the reaction)
Q7 Hard 5 marks Long Answer
Explain the cleansing action of soaps with the help of a labelled diagram. Why do soaps not work effectively in hard water? How are synthetic detergents different from soaps in their behaviour with hard water? Also write the chemical equation for the saponification reaction.
Q8 Hard 5 marks Case-Based
Riya's science teacher demonstrated the combustion of ethanol and methane in the laboratory. (i) Write the balanced chemical equations for the complete combustion of ethanol and methane. (ii) What products are formed during incomplete combustion of carbon compounds? Why is incomplete combustion a health hazard? (iii) Why is ethanol preferred as a fuel additive in some countries? Give one advantage and one disadvantage of its use.
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Previous Year Questions

From CBSE board examinations

Actual questions from past Class 10 Science board papers — Carbon and its Compounds chapter.

Board 20223 marks
What is a homologous series? Write the name and molecular formula of the second member of the homologous series whose first member is methanol. Also state two properties that are characteristic of a homologous series. (All India 2022)
Board 20232 marks
List two properties of carbon which lead to the formation of a very large number of carbon compounds. How are soaps different from detergents? Name one use of each. (Delhi 2023)
Board 20205 marks
Draw a labelled diagram to show the cleansing action of soap. Why do soaps not work in hard water? What are synthetic detergents? Give one advantage of using detergents over soaps. (CBSE 2020)
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FAQ

Questions teachers ask

How many marks does Carbon and its Compounds carry in the CBSE Class 10 board exam? +
Carbon and its Compounds typically carries 6–8 marks in the CBSE Class 10 Science board exam, spread across 3–4 questions — one 1-mark MCQ, one 2-mark short answer on functional groups or reactions, and one 3–5 mark question on nomenclature, properties, or chemical reactions. This chapter consistently appears in every CBSE Class 10 Science board paper.
What is the difference between saturated and unsaturated carbon compounds? +
Saturated compounds (alkanes) have only single C–C bonds and undergo substitution reactions with halogens in the presence of sunlight. Unsaturated compounds (alkenes with C=C double bonds, alkynes with C≡C triple bonds) undergo addition reactions — for example, ethene reacts with hydrogen in the presence of a nickel catalyst to form ethane. Board questions frequently ask students to distinguish these and predict the type of reaction.
What are homologous series and why are they important for board exams? +
A homologous series is a family of organic compounds that share the same general formula, functional group, and chemical properties, with consecutive members differing by a –CH₂– unit (14 mass units). For board exams, students must be able to identify whether a compound belongs to a homologous series, write the next member, and explain why physical properties (boiling point, solubility) change gradually while chemical properties remain similar.
How are IUPAC names assigned to simple carbon compounds in Class 10? +
At Class 10 level, IUPAC nomenclature involves identifying the parent carbon chain (meth-1C, eth-2C, prop-3C, but-4C, pent-5C), adding the appropriate suffix for the functional group (–ol for alcohols, –al for aldehydes, –oic acid for carboxylic acids, –one for ketones), and using prefixes like di- or tri- for multiple functional groups. Board questions typically ask students to name structures with 1–4 carbon atoms.
How do I generate a custom question paper for Carbon and its Compounds using MarksZen? +
Sign up for a free MarksZen account, choose CBSE Class 10 Science, select Chapter 4 (Carbon and its Compounds), set your preferred question-type mix (MCQ, short answer, diagram-based, long answer) and total marks — the AI generates a complete board-aligned paper with answer key in under 2 minutes, ready for PDF export.