🧪 Class 10 Chemistry — Carbon and Its Compounds FULL MASTER NOTES

CBSE Board 2026 | NCERT Based | Detailed Notes + Proper Diagrams + Tricks + PYQs + Important Questions

📖 INTRODUCTION

Carbon is one of the most important elements because all living organisms contain carbon compounds.

Carbon forms a very large number of compounds due to:

Tetravalency
Catenation

This chapter is extremely important for CBSE Board exams.

🌟 POSITION OF CARBON

Symbol → C
Atomic Number → 6
Electronic Configuration → 2,4

Carbon has 4 valence electrons.

🌟 WHY DOES CARBON FORM COVALENT BONDS? ⭐

Carbon neither loses nor gains 4 electrons because:

Losing 4 electrons requires huge energy.
Gaining 4 electrons makes atom unstable.

Therefore, carbon shares electrons and forms covalent bonds.

🌟 COVALENT BOND

Bond formed by sharing of electrons.

🌟 Example — Hydrogen Molecule

🌟 METHANE STRUCTURE (CH₄) ⭐ VERY IMPORTANT

Electron Dot Structure

Structural Formula

Explanation:

Carbon shares 4 electrons with hydrogen atoms.
Four covalent bonds are formed.

🌟 PROPERTIES OF COVALENT COMPOUNDS ⭐

Property	Reason
Low melting point	Weak intermolecular force
Low boiling point	Weak attraction
Poor conductors	No free ions
Mostly gases/liquids	Weak bonding

🌟 ALLOTROPES OF CARBON ⭐

Different forms of same element.

🌟 TYPES OF ALLOTROPES

Crystalline	Amorphous
Diamond	Coal
Graphite	Charcoal
Fullerene	Coke

🌟 DIAMOND STRUCTURE ⭐

         C
       / | \
      C--C--C
       \ | /
         C

Properties:

Hardest natural substance
Does not conduct electricity
Strong 3D structure

🌟 GRAPHITE STRUCTURE ⭐

C — C — C — C
|   |   |   |
C — C — C — C

Properties:

Conducts electricity
Soft and slippery
Layered structure

🌟 DIFFERENCE BETWEEN DIAMOND AND GRAPHITE ⭐

Diamond	Graphite
Hardest substance	Soft substance
Does not conduct electricity	Conducts electricity
3D structure	Layered structure

🌟 CATENATION ⭐ VERY IMPORTANT

Ability of carbon to form long chains with itself.

🌟 TYPES OF CARBON CHAINS

1. Straight Chain

C — C — C — C

Example:

Butane

2. Branched Chain

      C
      |
C — C — C

Example:

Isobutane

3. Ring Chain

    C —— C
   /      \
  C        C
   \      /
    C —— C

Example:

Cyclohexane

🌟 SATURATED AND UNSATURATED COMPOUNDS ⭐

Saturated Compound

Contains only single bonds.

Example:

Ethane

      H   H
      |   |
H — C — C — H
      |   |
      H   H

Formula:

Unsaturated Compound

Contains double or triple bonds.

Example 1 — Ethene

Formula:

Example 2 — Ethyne

H — C ≡ C — H

Formula:

🌟 DIFFERENCE BETWEEN SATURATED AND UNSATURATED COMPOUNDS

Saturated	Unsaturated
Single bonds only	Double/triple bonds
Less reactive	More reactive
Alkane family	Alkene/alkyne family

🌟 HYDROCARBONS ⭐

Compounds containing carbon and hydrogen only.

🌟 TYPES OF HYDROCARBONS

Type	Bond
Alkane	Single bond
Alkene	Double bond
Alkyne	Triple bond

🌟 HOMOLOGOUS SERIES ⭐ VERY IMPORTANT

Series of compounds having:

Same functional group
Similar chemical properties
Difference of CH₂ unit

🌟 HOMOLOGOUS SERIES DIAGRAM

CH₄  →  C₂H₆  →  C₃H₈  →  C₄H₁₀

🌟 FUNCTIONAL GROUPS ⭐ VERY IMPORTANT

Atom or group deciding chemical properties.

🌟 IMPORTANT FUNCTIONAL GROUPS

Functional Group	Structure
Alcohol	—OH
Aldehyde	—CHO
Carboxylic acid	—COOH

🌟 FUNCTIONAL GROUP DIAGRAM

Alcohol        →   —OH
Aldehyde       →   —CHO
Carboxylic acid→   —COOH

🌟 NOMENCLATURE OF CARBON COMPOUNDS ⭐

Prefix Based on Carbon Atoms

Carbon Atoms	Prefix
1	Meth
2	Eth
3	Prop
4	But

Suffix Based on Bonds

Bond Type	Suffix
Single	ane
Double	ene
Triple	yne

🌟 EXAMPLES

Formula	Name
CH₄	Methane
C₂H₆	Ethane
C₂H₄	Ethene
C₂H₂	Ethyne

🌟 CHEMICAL PROPERTIES OF CARBON COMPOUNDS

🧪 1. COMBUSTION ⭐

Carbon compounds burn in air producing CO₂ and water.

Combustion Diagram

Methane + Oxygen
        ↓
Carbon dioxide + Water + Heat

Equation

🌟 TYPES OF FLAME

Complete Combustion	Incomplete Combustion
Blue flame	Yellow flame
No soot	Soot formed

🧪 2. OXIDATION

Addition of oxygen.

Example

Oxidizing Agents:

Alkaline KMnO₄
Acidified K₂Cr₂O₇

🧪 3. ADDITION REACTION ⭐

Unsaturated compounds add hydrogen.

Diagram

Ethene + Hydrogen
        ↓
      Ethane

Equation

🌟 Hydrogenation

Vegetable oils convert into ghee.

🧪 4. SUBSTITUTION REACTION

Hydrogen atom replaced by another atom.

Equation

🌟 ETHANOL ⭐ VERY IMPORTANT

Formula: C₂H₅OH

Structure

CH₃ — CH₂ — OH

Uses:

Solvent
Medicines
Fuel

🌟 ETHANOIC ACID ⭐

Common name: Acetic acid

Formula: CH₃COOH

Structure

CH₃ — COOH

Properties:

Sour smell
Vinegar contains acetic acid

🌟 REACTION WITH BAKING SODA

🌟 ESTERIFICATION REACTION ⭐ VERY IMPORTANT

Alcohol + Carboxylic acid → Ester + Water

Diagram

Alcohol + Acid
      ↓
 Ester + Water

Equation

Uses of Esters:

Perfumes
Flavouring agents

🌟 SOAP AND DETERGENTS ⭐

SOAP

Sodium or potassium salts of fatty acids.

🌟 SOAP MICELLE DIAGRAM ⭐

       ○ ○ ○ ○ ○
     ○           ○
    ○    Dirt     ○
     ○           ○
       ○ ○ ○ ○ ○

Explanation:

Outer part → Hydrophilic head
Inner part → Hydrophobic tail
Dirt gets trapped inside

🌟 DIFFERENCE BETWEEN SOAP AND DETERGENT

Soap	Detergent
Works poorly in hard water	Works in hard water
Forms scum	No scum formed
Biodegradable	Some non-biodegradable

🎯 MOST IMPORTANT BOARD QUESTIONS WITH ANSWERS

Q1. Why does carbon form covalent bonds?

Answer:

Carbon neither loses nor gains 4 electrons because it requires huge energy. Therefore, carbon shares electrons and forms covalent bonds.

Q2. What is homologous series?

Answer:

A series of compounds having same functional group and similar chemical properties with difference of CH₂ is called homologous series.

Q3. Differentiate saturated and unsaturated compounds.

Saturated	Unsaturated
Single bonds only	Double/triple bonds
Less reactive	More reactive

Q4. What is esterification reaction?

Answer:

Reaction between alcohol and carboxylic acid producing ester and water is called esterification reaction.

Q5. Why do soaps not work in hard water?

Answer:

Soap reacts with calcium and magnesium salts forming scum, reducing cleansing action.

🧠 SUPER TRICKS

Hydrocarbon Series:

Alkane → Single bond
Alkene → Double bond
Alkyne → Triple bond

Functional Groups Trick:

“OH CHO COOH”

OH → Alcohol
CHO → Aldehyde
COOH → Carboxylic acid

🎯 EXPECTED QUESTIONS FOR CBSE BOARD 2026

Why does carbon form covalent bonds?
Explain homologous series.
Differentiate soaps and detergents.
Explain esterification reaction.
Explain cleansing action of soap.
Differentiate saturated and unsaturated compounds.
Explain properties of covalent compounds.
Explain diamond and graphite.

🧪 Carbon and Its Compounds — MCQs (PYQ Based)

CBSE Class 10 Science | Important MCQs with Answers | Board Exam 2026

📖 1. Carbon forms covalent bonds because:

A) It can donate four electrons

B) It can gain four electrons

C) It shares electrons to complete octet

D) It is a metal

✅ Answer: C) It shares electrons to complete octet

📖 2. Which of the following is a saturated hydrocarbon?

A) Ethene

B) Ethyne

C) Methane

D) Propene

✅ Answer: C) Methane

📖 3. The functional group present in alcohol is:

A) –CHO

B) –COOH

C) –OH

D) –CO

✅ Answer: C) –OH

📖 4. Ethanoic acid belongs to which homologous series?

A) Alcohols

B) Aldehydes

C) Carboxylic acids

D) Ketones

✅ Answer: C) Carboxylic acids

📖 5. Soap molecules have:

A) Only hydrophilic end

B) Only hydrophobic end

C) Both hydrophilic and hydrophobic ends

D) No charged end

✅ Answer: C) Both hydrophilic and hydrophobic ends

📖 6. The general formula of alkanes is:

A) CnH2n

B) CnH2n+2

C) CnH2n−2

D) CnHn

✅ Answer: B) CnH2n+2

📖 7. Which of the following undergoes addition reaction?

A) Methane

B) Ethane

C) Ethene

D) Propane

✅ Answer: C) Ethene

📖 8. The process of conversion of vegetable oil into vanaspati ghee is:

A) Oxidation

B) Hydrogenation

C) Fermentation

D) Esterification

✅ Answer: B) Hydrogenation

📖 9. The compound used in vinegar is:

A) Methanoic acid

B) Ethanoic acid

C) Propanoic acid

D) Butanoic acid

✅ Answer: B) Ethanoic acid

📖 10. Which of the following is the structural formula of ethanol?

A) CH3COOH

B) CH3OH

C) CH3CH2OH

D) CH4

✅ Answer: C) CH3CH2OH

📖 11. The cleansing action of soap is due to formation of:

A) Salts

B) Micelles

C) Crystals

D) Emulsion only

✅ Answer: B) Micelles

📖 12. Which gas is evolved during combustion of carbon compounds in sufficient oxygen?

A) CO

B) CO2

C) SO2

D) H2

✅ Answer: B) CO2

📖 13. Ethene contains:

A) Single bond only

B) Triple bond

C) Double bond

D) Ionic bond

✅ Answer: C) Double bond

📖 14. The suffix used for alcohols is:

A) –ane

B) –ene

C) –yne

D) –ol

✅ Answer: D) –ol

📖 15. Hard water does not form lather easily with:

A) Detergent

B) Soap

C) Shampoo

D) Acid

✅ Answer: B) Soap

🌟 Assertion–Reason MCQs

📖 16.

Assertion (A): Carbon forms a large number of compounds.

Reason (R): Carbon has property of catenation.

A) Both A and R are true and R is correct explanation

B) Both true but R not explanation

C) A true, R false

D) A false, R true

✅ Answer: A

📖 17.

Assertion (A): Saturated hydrocarbons are less reactive.

Reason (R): They contain only single covalent bonds.

✅ Answer: A

📖 18.

Assertion (A): Soap works poorly in hard water.

Reason (R): Soap forms scum with calcium and magnesium salts.

✅ Answer: A

🔥 Important Board PYQ Tips

✅ Learn all functional groups

✅ Practice homologous series

✅ Remember formulas of alkanes, alkenes, alkynes

✅ Revise soap vs detergent differences

✅ Learn chemical equations of:

Combustion

Esterification

Saponification

Hydrogenation