Master Carbon and Its Compounds Class 10 Notes – Key Concepts, Reactions & CBSE 2025

Carbon and Its Compounds Class 10 Notes

Hello Class 10 Science Champs! 👋

Struggling with Chapter 4 – Carbon and Its Compounds for your upcoming CBSE board exams? Don’t stress — we’re here to help you master it with confidence! 💪

In this blog, you’ll find clear, concise, and exam-ready notes that simplify even the most complex concepts. Whether it's understanding bonding, nomenclature, or reactions, we’ve got everything covered — and it’s all available in a free, downloadable PDF. 🎁

These aren’t just regular notes — they’re packed with real-life examples, visuals, and quick summaries to make your learning effective and enjoyable. 🧠✨

Ready to conquer Carbon and Its Compounds and score top marks? 😎 Let’s get started!

Subject	Science (Chemistry)
Class	10
Board	CBSE & State Boards
Chapter No.	4
Chapter Name	Carbon and its Compounds
Type	Notes
Session	2025-26

Bonding in Carbon - The Covalent Bond

Element	Carbon
Atomic Number	6
Electronic Configuration	2, 4
Valence Electrons	4 (Carbon is tetravalent because it has 4 valence electrons)
Valency	4

Carbon neither gains nor loses 4 electrons to attain the noble gas electronic configuration because:

It could gain four electrons forming C4– anion. But it would be difficult for the nucleus with six protons to hold on to ten electrons, that is, four extra electrons.
It could lose four electrons forming C4+ cation. But it would require a large amount of energy to remove four electrons leaving behind a carbon cation with six protons in its nucleus holding on to just two electrons.

Carbon overcomes this problem by sharing its valence electrons with other atoms of carbon or with atoms of other elements.

The shared electrons ‘belong’ to the outermost shells of both the atoms and lead to both atoms attaining the noble gas configuration.

Formation of Hydrogen molecule (H2)

formation of hydrogen molecule class 10 carbon and its compounds notes

Formation of Oxygen Molecule (O2)

formation of oxygen molecule class 10 carbon and its compounds notes

Formation of Nitrogen Molecule (N3)

formation of nitrogen molecule class 10 carbon and its compounds notes

Formation of Methane (CH4)

formation of methane class 10 carbon and its compounds notes — *Electron dot structure of methane*

Formation of Ethane (C2H6)

Electron dot structure of ethane class 10 carbon and its compounds notes — *Electron dot structure of ethane*

Formation of Ethene (C2H4)

Electron dot structure of ethene class 10 carbon and its compounds notes — *Electron dot structure of ethene*

Covalent Bond

Such bonds which are formed by the sharing of an electron pair between two atoms are known as covalent bonds.

Features of Covalent Compounds

Covalent compounds do not form ions, hence they are bad conductors of electricity.
The forces of attraction between the molecules are not very strong. Hence, covalent compounds have low melting and boiling points.

Versatile Nature of Carbon

The two properties of carbon that led to the huge number of carbon compounds are:

Carbon has the unique ability to form bonds with other atoms of carbon, giving rise to large molecules. This property is called catenation. (Carbon exhibits catenation much more than silicon or any other element due to its smaller size which makes the C-C bonds strong while the Si-Si bonds are comparatively weaker due to their larger size.)
Since carbon has a valency of four, it is capable of bonding with four other atoms of carbon or atoms of some other mono-valent element (Tetravalency).

Saturated and Unsaturated Carbon Compounds

Saturated Hydrocarbons	Unsaturated Hydrocarbons
1. Compounds of carbon having only a single bond between their carbon atoms are called saturated hydrocarbons.	1. Compounds of carbon having double or triple bonds between their carbon atoms are called unsaturated hydrocarbons.
2. Less reactive than unsaturated hydrocarbons.	2. More reactive than saturated hydrocarbons.
3. General formula is CnH2n+2.	3. General formula is CnH2n (alkenes) or CnH2n-2 (alkynes).
4. It burns with a clean flame.	4. It burns with a yellow sooty flame.
5. Substitution reaction is the characteristic property of these hydrocarbons.	5. Addition reaction is the characteristic property of these hydrocarbons.

Hydrocarbons: Carbon compounds that contain only carbon and hydrogen are called hydrocarbons.

Alkanes: The saturated hydrocarbons are called alkanes.

Alkenes: The unsaturated hydrocarbons which contain one or more double bonds are called alkenes.

Alkynes: The unsaturated hydrocarbons which contain one or more triple bonds are called alkynes.

Structural isomers: They have the same molecular formula but they differ in their structures.

Structural isomers of C4H6 are

HC ≡ C - CH2 - CH3
H3C - C ≡ C - CH3
H2C = C = CH - CH3
H2C =CH - CH =CH2

Saturated Ring: Example: cyclohexane (C6H12)

structure of cyclohexane class 10 science — *Structure of cyclohexane*

Unsaturated Ring: Example: benzene (C6H6)

structure of benzene class 10 science — *Structure of benzene*

functional group class 10 science chapter 4 notes — *Some functional groups in carbon compounds*

Homologous Series: A series of compounds in which the same functional group substitutes for hydrogen in a carbon chain is called a homologous series.

Example: CH3OH, C2H5OH, C3H7OH, C4H9OH, ….

Characteristics of homologous series:

It has a general formula in terms of the number of carbon atoms.
It has the same functional group.
The members of a homologous series i.e., homologues, have similar chemical properties.
The members of a homologous series i.e., homologues, show a gradation in physical properties with an increase in molecular mass.
Formulae of two successive homologues differ by -CH2- unit.
The difference in molecular mass between two successive homologues is 14 u.

Chemical Properties of Carbon Compounds

Combustion

Carbon burns in oxygen to give carbon dioxide along with the release of heat and light.

C + O2 → CO2 + heat and light
CH4 + O2 → CO2 + H2O + heat and light
CH3CH2OH (ethanol) + O2 → CO2 + H2O + heat and light

Oxidation

Carbon compounds can be easily oxidised on combustion.

Reactions in which alcohols are converted to carboxylic acids.

carbon and its compounds class 10 science notes

Alkaline potassium permanganate or acidified potassium dichromate are oxidising alcohols to acids, that is, adding oxygen to the starting material. Hence they are known as oxidising agents.

Addition Reaction

Hydrogenation: The addition of hydrogen to an unsaturated hydrocarbon to get a saturated hydrocarbon in presence of nickel or palladium as catalyst is called hydrogenation.

hydrogenation class 10 carbon and its compounds notes

This reaction is commonly used in the hydrogenation of vegetable oils using a nickel catalyst.

Vegetable oils generally have long unsaturated carbon chains while animal fats have saturated carbon chains.

Vegetable oils are ‘healthy’. Animal fats generally contain saturated fatty acids which are said to be harmful for health. Oils containing unsaturated fatty acids should be chosen for cooking.

Substitution Reaction

In the presence of sunlight, chlorine is added to hydrocarbons in a very fast reaction. Chlorine can replace the hydrogen atoms one by one.

CH4 + Cl2 → CH3Cl + HCl (in the presence of sunlight)

Some Important Carbon Compounds - Ethanol and Ethanoic Acid

Properties of Ethanol

Ethanol is a liquid at room temperature.
Ethanol is commonly called alcohol and is the active ingredient of all alcoholic drinks.
Ethanol is used to make cough syrups, tincture of iodine, etc.
It is also used as a fuel as an additive to petroleum.
Ethanol is soluble in water in all proportions.

Reactions of Ethanol

1. Reaction with sodium

2Na + 2CH3CH2OH → 2CH3CH2O–Na+ (sodium ethoxide) + H2

Alcohols react with sodium leading to the evolution of hydrogen. With ethanol, the other product is sodium ethoxide.

2. Reaction to give unsaturated hydrocarbon

Heating ethanol at 443 K with excess concentrated sulphuric acid results in the dehydration of ethanol to give ethene.

The concentrated sulphuric acid can be regarded as a dehydrating agent which removes water from ethanol.

Properties of Ethanoic Acid

Ethanoic acid is commonly called acetic acid and belongs to a group of acids called carboxylic acids.
5-8% solution of acetic acid in water is called vinegar and is used widely as a preservative in pickles.
The melting point of pure ethanoic acid is 290 K and hence it often freezes during winter in cold climates. This gave rise to its name glacial acetic acid.
Carboxylic acids are weak acids.

Reactions of ethanoic acid

1. Esterification reaction: Esters are most commonly formed by reaction of an acid and an alcohol. Ethanoic acid reacts with absolute ethanol in the presence of an acid catalyst to give an ester.

esterification reaction class 10 science

Esters are sweet-smelling substances. These are used in making perfumes and as flavouring agents.
Saponification is the process of converting esters into salts of carboxylic acids and ethanol by treating them with a base.

saponification reaction class 10 science

2. Reaction with a base

Ethanoic acid reacts with a base to give salt and water.

NaOH + CH3COOH → CH3COONa (sodium ethanoate/sodium acetate) + H2O

3. Reaction with carbonates and hydrogen carbonates: Ethanoic acid reacts with carbonates and hydrogen carbonates to give rise to salt, carbon dioxide, and water.

2CH3COOH + Na2CO3 → 2CH3COONa (sodium acetate) + H2O + CO2
CH3COOH + NaHCO3 → CH3COONa (sodium acetate) + H2O + CO2

Ethanol	Ethanoic Acid
(Difference in Physical properties)
1. It exists only in liquid form.	1. It can exist both in liquid and solid form.
2. Functional group is alcohol.	2. Functional group is carboxylic acid.
3. It has a specific smell but not like vinegar.	3. It smells like vinegar.
(Difference in Chemical properties)
4. Does not react with sodium bicarbonate.	4. Reacts with sodium bicarbonate to form salt, carbon dioxide, and water.
5. No effect on litmus paper.	5. It turns blue litmus paper red.

Soaps and Detergents

Cleansing action of soaps

Most dirt is oily in nature and oil does not dissolve in water. The molecules of soap are sodium or potassium salts of long-chain carboxylic acids. The ionic end of soap interacts with the water while the carbon chain interacts with oil. The soap molecules, thus form structures called micelles where one end of the molecules is towards the oil droplet while the ionic end faces outside. This forms an emulsion in water. The soap micelle thus helps in pulling out the dirt in water and we can wash our clothes clean.

Soap	Detergents
1. Molecules of soap are sodium or potassium salts of long-chain carboxylic acids.	1. Detergents are generally sodium salts of sulphonic acids or ammonium salts with chloride or bromide ions.
2. Not so effective in hard water.	2. It is effective even in hard water.
3. It forms scum in hard water.	3. Does not form scum in hard water.
4. It has poor foaming capacity.	4. It has a rich foaming capacity.
5. Soaps are biodegradable.	5. Most of the detergents are non-biodegradable.

The soluble salts of calcium and magnesium make the water hard.
Scum is formed by the reaction of calcium or magnesium ions with soap molecules. These ions react with soap molecules forming calcium or magnesium salts of long-chain carboxylic acids which are insoluble and precipitate out.
Detergents are generally sodium salts of sulphonic acids or ammonium salts with chlorides or bromides ions, etc.
The charged ends of these compounds do not form insoluble precipitates with the calcium and magnesium ions in hard water. Thus, they remain effective in hard water.

🧪 Chapter 4: Carbon and Its Compounds – NCERT Solutions

📚 Class 10 Science | NCERT Book | Full Solutions

📘 Intext Questions

🔹 Page 61

Q1. What would be the electron dot structure of carbon dioxide which has the formula CO₂?

✅ Answer:
Carbon has 4 valence electrons, and oxygen has 6 each.

$\text{O} = \text{C} = \text{O}$

The Lewis structure has double bonds between carbon and each oxygen.

Q2. What would be the electron dot structure of a molecule of sulphur which is made up of eight atoms of sulphur?

✅ Answer:
Sulphur forms a puckered S₈ ring. Each S atom shares 2 electrons with adjacent atoms forming a cyclic structure.

🔹 Page 62

Q1. How many structural isomers can you draw for pentane?
✅ Answer:
Three isomers:

n-pentane
Iso-pentane (2-methylbutane)
Neopentane (2,2-dimethylpropane)

Q2. What are the two properties of carbon which lead to the huge number of carbon compounds we see around us?

✅ Answer:

Catenation – Carbon's ability to form long chains
Tetravalency – Ability to form four covalent bonds

Q3. What will be the formula and electron dot structure of cyclopentane?

✅ Answer:
Formula: C₅H₁₀
Structure: Ring of five carbon atoms each bonded to two H atoms.

Q4. Draw the structures for the following compounds:

a) Ethanoic acid
b) Bromopentane
c) Butanone
d) Hexanal

✅ Answer:

a) CH₃COOH
b) CH₃CH₂CH₂CH₂CH₂Br (1-bromopentane; position varies by isomer)
c) CH₃CH₂COCH₃
d) CH₃CH₂CH₂CH₂CH₂CHO

🔹 Page 64

Q1. Would you be able to check if water is hard by using a detergent?

✅ Answer:
No, detergents form lather even in hard water. Soap is used to test hardness as it forms scum with hard water.

Q2. People use a variety of methods to wash clothes. Usually, after adding soap, they beat the clothes or agitate them. Why is agitation necessary to get clean clothes?

✅ Answer:
Agitation helps in emulsifying the dirt and oil particles trapped in micelles so they can be rinsed off with water.

📙 NCERT Exercise Questions (Back of the Chapter)

🔹 Q1. Ethane, with the molecular formula C₂H₆ has:

a) 6 covalent bonds
b) 7 covalent bonds
c) 8 covalent bonds
d) 9 covalent bonds

✅ Answer: (b) 7 covalent bonds

🔹 Q2. Butanone is a four-carbon compound with the functional group:

a) carboxylic acid
b) aldehyde
c) ketone
d) alcohol

✅ Answer: (c) ketone

🔹 Q3. While cooking, if the bottom of the vessel is getting blackened on the outside, it means that:

a) the food is not cooked completely
b) the fuel is not burning completely
c) the fuel is wet
d) the fuel is burning completely

✅ Answer: (b) the fuel is not burning completely

🔹 Q4. Explain the nature of the covalent bond using the bond formation in CH₄.

✅ Answer:
In methane (CH₄), carbon shares one electron with each of the four hydrogen atoms forming four covalent bonds.

🔹 Q5. Draw the electron dot structures for:

a) Ethyne
b) Ethene
c) Propane
d) Butanone

✅ Answer:

Ethyne: C≡C with one H on each carbon
Ethene: C=C with two H on each
Propane: CH₃–CH₂–CH₃
Butanone: CH₃–CO–CH₂–CH₃

🔹 Q6. What is a homologous series? Explain with an example.

✅ Answer:
A homologous series is a series of compounds with the same functional group and general formula, differing by –CH₂– group.
Example:
Alkanes – CH₄, C₂H₆, C₃H₈...

🔹 Q7. How can ethanol and ethanoic acid be differentiated on the basis of their physical and chemical properties?

✅ Answer:

Smell: Ethanoic acid has a vinegar-like smell
Reaction: Ethanoic acid reacts with NaHCO₃ (releases CO₂); ethanol does not
Solubility: Both soluble in water
Boiling Point: Ethanoic acid has a higher boiling point

🔹 Q8. Why does micelle formation occur only above a certain concentration of soap in water?

✅ Answer:
Because a minimum concentration (CMC – Critical Micelle Concentration) is needed for soap molecules to aggregate into micelles.

🔹 Q9. Why are carbon and its compounds used as fuels for most applications?

✅ Answer:
They have high calorific value and burn with a clean flame.

🔹 Q10. Explain the cleansing action of soaps.

✅ Answer:
Soap molecules have hydrophilic (water-loving) and hydrophobic (oil-loving) ends. They form micelles that trap grease and wash it away with water.

🧪 CBSE Class 10 Science – Chapter 4: Carbon and Its Compounds

📚 Past Year & Sample Questions with Marking Scheme

🔹 1-Mark Questions

What is the general formula of alkanes?
📅 CBSE 2020
✅ Answer: CₙH₂ₙ₊₂
Write the IUPAC name of CH₃–CH₂–COOH.
📅 CBSE 2023
✅ Answer: Propanoic acid
What is a functional group? Give one example.
📅 CBSE 2018
✅ Answer: An atom or group of atoms responsible for the characteristic reactions of a compound. Example: –OH in alcohol.
Write the molecular formula of benzene.
📅 CBSE 2019
✅ Answer: C₆H₆

🔹 2-Mark Questions

Give reasons:
- a) Carbon forms covalent bonds.
- b) Covalent compounds have low melting and boiling points.
  📅 CBSE 2020

✅ Answer:
a) Carbon has 4 valence electrons and cannot lose or gain 4 electrons easily.
b) Covalent bonds do not have strong electrostatic forces, so melting/boiling points are low.

Write the electron dot structure of ethyne. What type of bond is present?
📅 CBSE 2021
✅ Answer:
Triple covalent bond between two carbon atoms; C≡C.

🔹 3-Mark Questions

State the properties of covalent compounds. Why do they not conduct electricity?
📅 CBSE 2018
✅ Answer:

Low melting/boiling points
Poor conductivity
Insoluble in water
They do not form ions, so no current flows.

Differentiate between saturated and unsaturated hydrocarbons with two examples each.
📅 CBSE 2019
✅ Answer:
Saturated: Single bonds (e.g., ethane, propane)
Unsaturated: Double/triple bonds (e.g., ethene, ethyne)
What is saponification? Write the chemical equation involved.
📅 CBSE 2022
✅ Answer:
Saponification: Reaction of esters with alkali to form soap and alcohol.
CH₃COOC₂H₅ + NaOH → CH₃COONa + C₂H₅OH

🔹 4-Mark Questions (Assertion/Reason, Case-Based)

Assertion (A): Ethanoic acid reacts with sodium carbonate to produce carbon dioxide.
Reason (R): All acids react with carbonates to produce carbon dioxide.
📅 CBSE Sample Paper 2023
✅ Answer: Both A and R are true, and R is the correct explanation.

Case-Based Question:

A student prepared soap in the lab by saponification. After filtering the mixture, he tested the residue.

Q1. What is the residue and why is it formed?
Q2. What is micelle formation? How does soap clean greasy dirt?
📅 CBSE Sample Paper 2024

✅ Answer:

The residue is soap; it forms as an insoluble product.
Micelles trap grease in their center and get rinsed away with water.

🔹 5-Mark Questions

Explain the process of soap formation with a suitable chemical equation. Why is soap not effective in hard water?

📅 CBSE 2018
✅ Answer:
Saponification reaction:
Fat + NaOH → Soap + Glycerol
Soap forms scum with calcium/magnesium ions in hard water, reducing cleansing power.

Explain the chemical properties of ethanol. Give two reactions with balanced equations. Mention one use of ethanol.
📅 CBSE 2020
✅ Answer:

Reaction with sodium:
2C₂H₅OH + 2Na → 2C₂H₅ONa + H₂
Combustion:
C₂H₅OH + 3O₂ → 2CO₂ + 3H₂O
Use: In making alcoholic beverages, sanitizers

What are homologous series? State its characteristics. Write the next two members after butyne.
📅 CBSE 2021
✅ Answer:
A group with same functional group and formula. Characteristics:

Same functional group
Successive members differ by –CH₂
Next members: Pentyne (C₅H₈), hexyne (C₆H₁₀)

📌 CBSE Exam Focus: High-Frequency Topics

Topic	Type of Questions	Frequency
Properties of Covalent Compounds	1M, 2M, 3M	Very High
Nomenclature & Structural Formula	1M, 3M	High
Homologous Series	2M, 5M	High
Saponification & Soaps	3M, 5M	Medium
Reactions of Ethanol & Acids	3M, 5M	High
Micelle Formation	Case-Based, 4M	Medium
Electron Dot Structures	1M, 2M	High