CBSE Class 10 Science Chapter 4 Carbon and Its Compounds

Carbon and Its Compounds is a chapter in your science subject. Radhe Radhe to all my dear children! You all will have to work very hard for your board exams to get good marks. In this post, I will try to cover all the important topics of your 10th-grade science syllabus so that you can understand and remember them.

Carbon and Its Compounds, which is your fourth chapter, falls under the chemistry section of science. All the information you need to study in this chapter will be found in this post.

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Table of Contents

Key Content of Chapter 4 Carbon and Its Compounds

1️⃣ Importance of Carbon

Carbon is the basis of life
Food, clothes, medicines, fuels → all are carbon compounds
Very small amount in nature:
- Earth’s crust: 0.02%
- Atmosphere (CO₂): 0.03%
Still forms millions of compounds

2️⃣ Bonding in Carbon – Covalent Bond

Carbon atomic number = 6
Valence electrons = 4
Cannot form C⁴⁺ or C⁴⁻ easily
So carbon shares electrons → covalent bond

Properties of Covalent Compounds

Low melting & boiling points
Poor conductors of electricity
Molecules, not ions

Examples

H₂ → single bond
O₂ → double bond
N₂ → triple bond
CH₄ (methane) → carbon shares electrons with 4 H atoms

3️⃣ Allotropes of Carbon

Different physical forms, same chemical nature:

🔹 Diamond

Each C bonded to 4 C atoms
Hardest substance
Non-conductor of electricity

🔹 Graphite

Each C bonded to 3 C atoms
Soft, slippery
Good conductor of electricity

Fullerenes (C₆₀)

Football-like structure
New allotrope of carbon

4️⃣ Versatile Nature of Carbon

Carbon forms huge number of compounds due to:

(i) Catenation

Ability to form long chains, branches & rings
Strong C–C bond

(ii) Tetravalency

Carbon forms 4 covalent bonds
Bonds with H, O, N, Cl, S etc.

5️⃣ Saturated & Unsaturated Hydrocarbons

🔹 Saturated Compounds (Alkanes)

Only single bonds
Less reactive
Example: Methane (CH₄), Ethane (C₂H₆)

🔹 Unsaturated Compounds

Double bond → Alkenes (C₂H₄)
Triple bond → Alkynes (C₂H₂)
More reactive

6️⃣ Chains, Branches & Rings

Carbon chains can be:
- Straight
- Branched
- Cyclic (e.g. cyclohexane)

Structural Isomerism

Same molecular formula, different structure
Example: Butane (C₄H₁₀) has two isomers

7️⃣ Functional Groups

Replace H in hydrocarbon → change properties

Functional Group	Formula	Class
Alcohol	–OH	Alcohol
Aldehyde	–CHO	Aldehyde
Ketone	–CO–	Ketone
Carboxylic acid	–COOH	Acid
Halogen	–Cl / –Br	Haloalkane

8️⃣ Homologous Series

Series of compounds with:
- Same functional group
- Same general formula
- Difference of –CH₂–
Chemical properties → same
Physical properties → gradual change

9️⃣ Nomenclature of Carbon Compounds

Based on:

Number of carbon atoms
Saturation
Functional group

Examples:

Alcohol → suffix –ol
Acid → suffix –oic acid
Alkene → –ene
Alkyne → –yne

🔟 Chemical Properties of Carbon Compounds

(i) Combustion

Carbon compounds burn → CO₂ + H₂O + heat
Incomplete combustion → soot

(ii) Oxidation

Alcohol → Acid
Oxidising agents:
- KMnO₄
- K₂Cr₂O₇

(iii) Addition Reaction

Unsaturated hydrocarbons + H₂ → Saturated
Catalyst: Ni / Pd
Used in hydrogenation of oils

(iv) Substitution Reaction

Saturated hydrocarbons + Cl₂ (sunlight)
H replaced by Cl

1️⃣1️⃣ Ethanol (C₂H₅OH)

Properties

Colourless liquid
Soluble in water
Used in medicines, fuel, beverages

Reactions

With Na → Hydrogen gas
Dehydration → Ethene

⚠️ Excess intake harmful
Methanol → highly poisonous

1️⃣2️⃣ Ethanoic Acid (CH₃COOH)

Properties

Weak acid
Vinegar = 5–8% solution
Freezes in winter → glacial acetic acid

Reactions

With alcohol → Ester (sweet smell)
With base → Salt + water
With carbonates → CO₂

1️⃣3️⃣ Soaps and Detergents

Soaps

Sodium/potassium salts of fatty acids
Work by micelle formation
Not effective in hard water

Detergents

Work in hard & soft water
Do not form scum

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Class 10 Science Chapter 4 Carbon and Its Compounds Notes

CBSE Class 10 Science – Chapter 4

Carbon and Its Compounds

Complete Class 10 Science Chapter 4 notes, NCERT book PDF aur official Telegram channel ka direct access yahan se milega.

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Science Chapter 4 Carbon and Its Compounds MCQs

Q1. Carbon usually forms which type of bond?

A. Ionic bond

B. Covalent bond

C. Metallic bond

D. Hydrogen bond

✅ Correct Answer: Covalent bond

Q2. Valency of carbon is:

A. 2

B. 3

C. 4

D. 6

✅ Correct Answer: 4

Q3. Carbon compounds have low melting point because:

A. Strong intermolecular force

B. Weak intermolecular force

C. Ionic bonding

D. High density

✅ Correct Answer: Weak intermolecular force

Q4. The ability of carbon to form long chains is called:

A. Saturation

B. Catenation

C. Reduction

D. Oxidation

✅ Correct Answer: Catenation

Q5. Methane (CH₄) is a:

A. Saturated hydrocarbon

B. Unsaturated hydrocarbon

C. Alcohol

D. Acid

✅ Correct Answer: Saturated hydrocarbon

Q6. Ethene (C₂H₄) contains:

A. Single bond only

B. Double bond

C. Triple bond

D. Ionic bond

✅ Correct Answer: Double bond

Q7. Same molecular formula but different structure are called:

A. Homologues

B. Isomers

C. Allotropes

D. Radicals

✅ Correct Answer: Isomers

Q8. Diamond and graphite differ in:

A. Chemical properties

B. Arrangement of carbon atoms

C. Atomic number

D. Composition

✅ Correct Answer: Arrangement of carbon atoms

Q9. Graphite conducts electricity due to:

A. Ionic bonding

B. Free electrons

C. High density

D. Hard structure

✅ Correct Answer: Free electrons

Q10. Homologous series members differ by:

A. –OH

B. –CH₂

C. –COOH

D. –H

✅ Correct Answer: –CH₂

Q11. Functional group –OH represents:

A. Alcohol

B. Acid

C. Ketone

D. Aldehyde

✅ Correct Answer: Alcohol

Q12. Alkenes ka general formula hota hai:

A. CnH2n+2

B. CnH2n

C. CnH2n–2

D. CnHn

✅ Correct Answer: CnH2n

Q13. Unsaturated hydrocarbons show:

A. Addition reaction

B. Substitution reaction

C. Neutralisation

D. Displacement

✅ Correct Answer: Addition reaction

Q14. Ethanol reacts with sodium to form:

A. Sodium hydroxide

B. Sodium ethoxide

C. Sodium acetate

D. Sodium chloride

✅ Correct Answer: Sodium ethoxide

Q15. Vinegar contains:

A. Methanoic acid

B. Ethanoic acid

C. Lactic acid

D. Citric acid

✅ Correct Answer: Ethanoic acid

Q16. Esterification produces:

A. Salt

B. Ester

C. Gas

D. Base

✅ Correct Answer: Ester

Q17. Soap cleans due to formation of:

A. Precipitate

B. Micelles

C. Salts

D. Foam only

✅ Correct Answer: Micelles

Q18. Hard water contains salts of:

A. Sodium & potassium

B. Calcium & magnesium

C. Iron & copper

D. Zinc & aluminium

✅ Correct Answer: Calcium & magnesium

Q19. Detergents are effective in hard water because:

A. They form scum

B. They do not form precipitate

C. They are acidic

D. They are neutral

✅ Correct Answer: They do not form precipitate

Q20. Carbon compounds are poor conductors because:

A. High density

B. No free ions

C. Strong acids

D. Metallic nature

✅ Correct Answer: No free ions

Also Read- CBSE Class 10 Science Chapter 3 Metals and Non-metals

FAQs About Carbon and Its Compounds

Q1. Why does carbon form covalent bonds instead of ionic bonds?

Carbon has four valence electrons. It cannot easily lose or gain four electrons, so it shares electrons with other atoms to complete its octet, forming covalent bonds.

Q2. Why do carbon compounds have low melting and boiling points?

Carbon compounds have weak intermolecular forces of attraction, which results in low melting and boiling points compared to ionic compounds.

Q3. What is meant by catenation?

Catenation is the property of carbon to form long chains, branched chains or rings by bonding with other carbon atoms through single, double or triple bonds.

Q4. What are saturated and unsaturated hydrocarbons?

Saturated hydrocarbons contain only single bonds between carbon atoms, while unsaturated hydrocarbons contain one or more double or triple bonds.

Q5. What are homologous series?

A homologous series is a group of carbon compounds having the same functional group and similar chemical properties, where successive members differ by a –CH₂ unit.

Q6. Why do diamond and graphite have different properties?

Diamond and graphite differ due to different arrangements of carbon atoms. Diamond has a rigid 3D structure, while graphite has layered hexagonal structures.

Q7. Why does graphite conduct electricity?

In graphite, each carbon atom is bonded to three others, leaving one free electron which can move freely and conduct electricity.

Q8. What is ethanol and mention one of its uses?

Ethanol is an alcohol (C₂H₅OH). It is used as a solvent in medicines and as a fuel additive because it burns cleanly.

Q9. What is ethanoic acid commonly known as?

Ethanoic acid is commonly known as acetic acid. A 5–8% solution of ethanoic acid in water is called vinegar.

Q10. How do soaps clean oily dirt?

Soap molecules form micelles in water. The hydrophobic end traps oily dirt, while the hydrophilic end dissolves in water, allowing dirt to be washed away.