Class 10th Science Chapter 4 – Carbon and Its Compounds | Ethanol – Properties, Reactions and Uses

Carbon and Its Compounds

Ethanol – Properties, Reactions and Uses

एथेनॉल – गुण, अभिक्रियाएँ एवं उपयोग

Class 10 Science | CBSE + Foundation + Competitive

Ethanol – Properties, Reactions and Uses

1. Ethanol – Introduction | एथेनॉल का परिचय

English:
Ethanol is an important member of the alcohol family. It contains the functional group –OH attached to a carbon atom. Its molecular formula is C₂H₅OH or C₂H₆O. Its structural formula is:

CH₃–CH₂–OH

Hindi:
एथेनॉल अल्कोहल वर्ग का एक महत्वपूर्ण कार्बनिक यौगिक है। इसमें –OH (हाइड्रॉक्सिल) क्रियात्मक समूह उपस्थित होता है। इसका आणविक सूत्र C₂H₅OH है।

Important Facts – महत्वपूर्ण तथ्य

Molecular Formula = C₂H₅OH
Structural Formula = CH₃–CH₂–OH
Functional Group = –OH
IUPAC Name = Ethanol
Common Name = Ethyl Alcohol

2. Structure of Ethanol – एथेनॉल की संरचना

Ethanol contains two carbon atoms. The –OH group is attached to the second carbon atom.

एथेनॉल में दो कार्बन परमाणु होते हैं तथा –OH समूह कार्बन श्रृंखला के एक सिरे पर जुड़ा होता है।

H₃C–CH₂–OH

Feature	Ethanol
Number of Carbon atoms	2
Formula	C₂H₅OH
Functional group	–OH
Family	Alcohol
IUPAC name	Ethanol

3. Physical Properties of Ethanol – एथेनॉल के भौतिक गुण

• Ethanol is a colourless liquid.
  एथेनॉल एक रंगहीन द्रव है।
• It has a characteristic smell.
  इसकी एक विशिष्ट गंध होती है।
• It is highly volatile.
  यह अत्यधिक वाष्पशील होता है।
• It is miscible with water in all proportions.
  यह जल में सभी अनुपातों में मिश्रित हो सकता है।
• It is a good solvent for many organic substances.
  यह कई कार्बनिक पदार्थों के लिए अच्छा विलायक है।
• It is highly inflammable.
  यह अत्यधिक ज्वलनशील है।

Exam Point:
Ethanol is completely miscible with water because its –OH group can form hydrogen bonds with water molecules.

एथेनॉल जल के साथ हाइड्रोजन बंध बना सकता है, इसी कारण यह जल में अच्छी तरह मिश्रित होता है।

4. Chemical Properties of Ethanol – एथेनॉल के रासायनिक गुण

The important reactions of ethanol are:

1. Reaction with Sodium
2. Oxidation
3. Dehydration
4. Combustion

5. Reaction of Ethanol with Sodium – सोडियम के साथ अभिक्रिया

English:
Ethanol reacts with sodium metal to form sodium ethoxide and hydrogen gas.

Hindi:
एथेनॉल सोडियम धातु के साथ अभिक्रिया करके सोडियम एथॉक्साइड तथा हाइड्रोजन गैस बनाता है।

2C₂H₅OH + 2Na → 2C₂H₅ONa + H₂↑

Observation – अवलोकन:

Effervescence due to the evolution of hydrogen gas can be observed.

हाइड्रोजन गैस निकलने के कारण बुलबुले/फेन दिखाई देते हैं।

Important: This reaction shows that the hydrogen of the –OH group can be replaced by sodium.

6. Oxidation of Ethanol – एथेनॉल का ऑक्सीकरण

Ethanol is oxidised to ethanoic acid using an oxidising agent such as alkaline potassium permanganate (KMnO₄) or acidified potassium dichromate (K₂Cr₂O₇).

एथेनॉल का ऑक्सीकरण करके एथेनोइक अम्ल प्राप्त किया जा सकता है। इसके लिए KMnO₄ या K₂Cr₂O₇ जैसे ऑक्सीकारकों का उपयोग किया जाता है।

CH₃CH₂OH + 2[O] → CH₃COOH + H₂O

Ethanol → Oxidation → Ethanoic Acid

एथेनॉल → ऑक्सीकरण → एथेनोइक अम्ल

7. Dehydration of Ethanol – एथेनॉल का निर्जलीकरण

English:
When ethanol is heated with concentrated sulphuric acid at about 443 K, it loses water and forms ethene.

Hindi:
जब एथेनॉल को लगभग 443 K तापमान पर सांद्र सल्फ्यूरिक अम्ल के साथ गर्म किया जाता है, तब इससे जल निकल जाता है और एथीन बनता है।

C₂H₅OH    conc. H₂SO₄    443 K → C₂H₄ + H₂O

Reaction Type:
Dehydration reaction / Elimination reaction

अभिक्रिया का प्रकार:
निर्जलीकरण / विलोपन अभिक्रिया

Memory Trick:

Ethanol loses H₂O → Ethene
C₂H₅OH → C₂H₄ + H₂O

8. Combustion of Ethanol – एथेनॉल का दहन

Ethanol burns in oxygen with a clean flame and releases a large amount of heat.

एथेनॉल ऑक्सीजन में जलकर ऊष्मा उत्पन्न करता है।

C₂H₅OH + 3O₂ → 2CO₂ + 3H₂O + Heat

Use as Fuel:
Because ethanol releases heat on combustion, it can be used as a fuel and is also blended with petrol in some applications.

9. Ethanol and Ethanoic Acid – एथेनॉल एवं एथेनोइक अम्ल

Ethanol can be oxidised to ethanoic acid.

एथेनॉल का ऑक्सीकरण होने पर एथेनोइक अम्ल प्राप्त होता है।

CH₃CH₂OH → CH₃COOH

Very Important Conversion:

Alcohol → Carboxylic Acid
Ethanol → Ethanoic Acid

10. Uses of Ethanol – एथेनॉल के उपयोग

1. As a Solvent – विलायक के रूप में
Ethanol is used as a solvent in medicines, perfumes, cosmetics and many laboratory preparations.

एथेनॉल का उपयोग दवाइयों, इत्र, कॉस्मेटिक्स तथा प्रयोगशाला में विलायक के रूप में किया जाता है।

2. As a Fuel – ईंधन के रूप में
Ethanol can be used as a fuel because it burns and releases heat.

एथेनॉल ईंधन के रूप में उपयोग किया जा सकता है क्योंकि यह जलकर ऊष्मा उत्पन्न करता है।

3. Petrol Blending – पेट्रोल में मिश्रण
Ethanol is blended with petrol in fuel applications.

ईंधन के रूप में एथेनॉल को पेट्रोल के साथ मिश्रित किया जा सकता है।

4. Medicines and Pharmaceuticals – औषधियों में
Ethanol is used as a solvent and processing ingredient in various pharmaceutical preparations.

5. Perfumes and Cosmetics – इत्र एवं कॉस्मेटिक्स
It is used as a solvent in perfumes and several cosmetic products.

6. Laboratory Use – प्रयोगशाला उपयोग
Ethanol is commonly used as a solvent and cleaning agent in laboratory settings.

11. Harmful Effects of Excessive Alcohol Consumption
अधिक मात्रा में अल्कोहल सेवन के हानिकारक प्रभाव

English:
Ethanol is the alcohol present in alcoholic beverages. Excessive consumption can seriously affect the nervous system, liver and other organs.

Hindi:
एथेनॉल ही वह अल्कोहल है जो मादक पेय पदार्थों में पाया जाता है। अधिक मात्रा में इसका सेवन तंत्रिका तंत्र, यकृत तथा अन्य अंगों पर गंभीर प्रभाव डाल सकता है।

Exam Point:
Pure ethanol should never be confused with "drinking alcohol" as a safe substance. Excessive ethanol intake is harmful.

12. Important Reactions of Ethanol – एथेनॉल की महत्वपूर्ण अभिक्रियाएँ

Reaction	Equation	Product
With Sodium	2C₂H₅OH + 2Na → 2C₂H₅ONa + H₂	Sodium ethoxide
Oxidation	CH₃CH₂OH + 2[O] → CH₃COOH + H₂O	Ethanoic acid
Dehydration	C₂H₅OH → C₂H₄ + H₂O	Ethene
Combustion	C₂H₅OH + 3O₂ → 2CO₂ + 3H₂O	CO₂ + H₂O + Heat

13. Ethanol vs Ethene – एथेनॉल एवं एथीन

Property	Ethanol	Ethene
Formula	C₂H₅OH	C₂H₄
Functional group	–OH	C=C
Type	Alcohol	Unsaturated hydrocarbon
Important reaction	Oxidation	Addition

14. 30 MCQs – बहुविकल्पीय प्रश्न

Q1. The molecular formula of ethanol is:

A) CH₄

B) C₂H₆

C) C₂H₅OH

D) C₂H₄

Answer: C) C₂H₅OH

Q2. The functional group present in ethanol is:

A) –OH

B) –COOH

C) –CHO

D) –Cl

Answer: A) –OH

Q3. The IUPAC name of ethyl alcohol is:

A) Methanol

B) Ethanol

C) Ethanal

D) Ethanoic acid

Answer: B) Ethanol

Q4. Ethanol reacts with sodium to produce:

A) Oxygen

B) Nitrogen

C) Carbon dioxide

D) Hydrogen

Answer: D) Hydrogen

Q5. Which compound is obtained by oxidation of ethanol?

A) Ethene

B) Ethanoic acid

C) Methane

D) Ethane

Answer: B) Ethanoic acid

Q6. Which reagent can oxidise ethanol?

A) KMnO₄

B) NaCl

C) H₂

D) CH₄

Answer: A) KMnO₄

Q7. Ethanol heated with concentrated H₂SO₄ at about 443 K gives:

A) Ethane

B) Methane

C) Ethene

D) Ethanoic acid

Answer: C) Ethene

Q8. The dehydration of ethanol produces:

A) Ethene

B) Ethane

C) Methane

D) Ethanoic acid

Answer: A) Ethene

Q9. Which acid is used for dehydration of ethanol?

A) HCl

B) H₂SO₄

C) HNO₃

D) CH₃COOH

Answer: B) H₂SO₄

Q10. Ethanol burns to produce:

A) CO₂ and H₂O

B) CO and H₂

C) CH₄ only

D) O₂ and H₂

Answer: A) CO₂ and H₂O

Q11. Ethanol is commonly used as:

A) Metal

B) Solvent

C) Salt

D) Oxide

Answer: B) Solvent

Q12. Ethanol belongs to the family of:

A) Aldehydes

B) Ketones

C) Alcohols

D) Acids

Answer: C) Alcohols

Q13. The structural formula of ethanol is:

A) CH₃OH

B) CH₃CH₂OH

C) CH₃COOH

D) CH₄

Answer: B) CH₃CH₂OH

Q14. Ethanol is:

A) Colourless liquid

B) Black solid

C) Green gas

D) Blue solid

Answer: A) Colourless liquid

Q15. Ethanol is:

A) Non-flammable

B) Highly inflammable

C) Metallic

D) Ionic solid

Answer: B) Highly inflammable

Q16. The product formed when ethanol reacts with sodium is:

A) Sodium chloride

B) Sodium ethoxide

C) Sodium carbonate

D) Sodium hydroxide

Answer: B) Sodium ethoxide

Q17. Which gas is evolved when ethanol reacts with sodium?

A) H₂

B) O₂

C) CO₂

D) Cl₂

Answer: A) H₂

Q18. The product of dehydration of ethanol is:

A) Ethanol

B) Ethanoic acid

C) Ethene

D) Methane

Answer: C) Ethene

Q19. Ethanol is miscible with:

A) Water

B) Iron

C) Sand

D) Copper

Answer: A) Water

Q20. Which process converts ethanol into ethanoic acid?

A) Addition

B) Oxidation

C) Substitution

D) Neutralisation

Answer: B) Oxidation

Q21. Ethanol contains how many carbon atoms?

A) 1

B) 2

C) 3

D) 4

Answer: B) 2

Q22. The common name of ethanol is:

A) Ethyl alcohol

B) Methyl alcohol

C) Acetic acid

D) Formaldehyde

Answer: A) Ethyl alcohol

Q23. Which group makes ethanol an alcohol?

A) –COOH

B) –CHO

C) –OH

D) –CO–

Answer: C) –OH

Q24. Ethanol reacts with sodium according to:

A) 2C₂H₅OH + 2Na → 2C₂H₅ONa + H₂

B) C₂H₅OH + O₂ → CO₂

C) C₂H₅OH → CH₄

D) C₂H₅OH + NaCl → NaOH

Answer: A)

Q25. At about 443 K, ethanol with concentrated H₂SO₄ forms:

A) Ethene

B) Ethane

C) Methane

D) Ethanoic acid

Answer: A) Ethene

Q26. Ethanol can be used as:

A) Fuel

B) Solvent

C) Both A and B

D) Neither

Answer: C) Both A and B

Q27. Which compound is formed by oxidation of ethanol?

A) CH₃COOH

B) CH₄

C) C₂H₄

D) C₂H₆

Answer: A) CH₃COOH

Q28. The dehydration reaction removes:

A) Oxygen only

B) Water

C) Carbon dioxide

D) Hydrogen chloride

Answer: B) Water

Q29. Which statement is correct?

A) Ethanol contains –OH group

B) Ethanol is a metal

C) Ethanol is an ionic salt

D) Ethanol contains no carbon

Answer: A) Ethanol contains –OH group

Q30. Which sequence is correct?

A) Ethanol → Oxidation → Ethanoic acid

B) Ethanol → Sodium → CO₂ only

C) Ethanol → Dehydration → Methane

D) Ethanol → Oxidation → Ethene

Answer: A) Ethanol → Oxidation → Ethanoic acid

15. 30 Subjective Questions – वर्णनात्मक प्रश्न

1 Mark Q1. Write the molecular formula of ethanol.

Answer: C₂H₅OH.

1 Mark Q2. Name the functional group present in ethanol.

Answer: Hydroxyl group (–OH).

1 Mark Q3. What is the IUPAC name of ethyl alcohol?

Answer: Ethanol.

1 Mark Q4. How many carbon atoms are present in ethanol?

Answer: Two.

1 Mark Q5. Name the gas evolved when ethanol reacts with sodium.

Answer: Hydrogen gas.

2 Marks Q6. Write the structural formula of ethanol.

Answer:

CH₃–CH₂–OH

2 Marks Q7. Write the reaction of ethanol with sodium.

2C₂H₅OH + 2Na → 2C₂H₅ONa + H₂↑

2 Marks Q8. What happens when ethanol is oxidised?

Ethanol is oxidised to ethanoic acid.

CH₃CH₂OH + 2[O] → CH₃COOH + H₂O

2 Marks Q9. What is dehydration of ethanol?

Removal of water from ethanol on heating with concentrated H₂SO₄ is called dehydration.

C₂H₅OH → C₂H₄ + H₂O

2 Marks Q10. Write two uses of ethanol.

1. As a solvent.
2. As a fuel.

3 Marks Q11. Write three physical properties of ethanol.

• It is a colourless liquid.
• It is highly volatile.
• It is miscible with water.

3 Marks Q12. Explain the reaction of ethanol with sodium.

Ethanol reacts with sodium to form sodium ethoxide and hydrogen gas.

2C₂H₅OH + 2Na → 2C₂H₅ONa + H₂↑

Hydrogen gas is evolved during the reaction.

3 Marks Q13. Explain oxidation of ethanol.

Ethanol is oxidised in the presence of an oxidising agent such as KMnO₄ or K₂Cr₂O₇.

CH₃CH₂OH + 2[O] → CH₃COOH + H₂O

Ethanoic acid is formed.

3 Marks Q14. Explain dehydration of ethanol.

Ethanol is heated with concentrated H₂SO₄ at about 443 K. Water is removed and ethene is formed.

C₂H₅OH → C₂H₄ + H₂O

3 Marks Q15. Why is ethanol used as a solvent?

Ethanol can dissolve many organic substances and is also miscible with water. Therefore it is useful as a solvent in medicines, perfumes and laboratory preparations.

4 Marks Q16. Explain four important chemical reactions of ethanol.

1. With Sodium:
2C₂H₅OH + 2Na → 2C₂H₅ONa + H₂

2. Oxidation:
CH₃CH₂OH + 2[O] → CH₃COOH + H₂O

3. Dehydration:
C₂H₅OH → C₂H₄ + H₂O

4. Combustion:
C₂H₅OH + 3O₂ → 2CO₂ + 3H₂O + Heat

4 Marks Q17. Write four physical properties of ethanol.

• Colourless liquid.
• Characteristic smell.
• Highly volatile.
• Miscible with water.

4 Marks Q18. Explain the uses of ethanol.

Ethanol is used:

• As a solvent.
• As a fuel.
• In pharmaceutical preparations.
• In perfumes and cosmetics.

4 Marks Q19. Write the reaction for conversion of ethanol into ethene.

Ethanol is heated with concentrated sulphuric acid at about 443 K.

C₂H₅OH   conc. H₂SO₄, 443 K   → C₂H₄ + H₂O

4 Marks Q20. Explain why ethanol is miscible with water.

The –OH group of ethanol can form hydrogen bonds with water molecules. Due to this interaction, ethanol mixes with water in all proportions.

5 Marks Q21. Describe the physical and chemical properties of ethanol.

Physical properties:

• Colourless liquid.
• Volatile.
• Miscible with water.
• Characteristic smell.

Chemical properties:

• Reacts with sodium.
• Undergoes oxidation.
• Undergoes dehydration.
• Undergoes combustion.

5 Marks Q22. Explain the oxidation and dehydration reactions of ethanol.

Oxidation:
CH₃CH₂OH + 2[O] → CH₃COOH + H₂O

Ethanol changes into ethanoic acid.

Dehydration:
C₂H₅OH → C₂H₄ + H₂O

Concentrated H₂SO₄ and about 443 K are used.

5 Marks Q23. Explain the reaction of ethanol with sodium and state the observation.

Ethanol reacts with sodium to produce sodium ethoxide and hydrogen gas.

2C₂H₅OH + 2Na → 2C₂H₅ONa + H₂↑

Observation: Effervescence occurs due to evolution of hydrogen gas.

5 Marks Q24. Explain why ethanol is important in daily life.

Ethanol has several applications:

• Used as a solvent.
• Used in pharmaceutical preparations.
• Used in perfumes and cosmetics.
• Used as a fuel.
• Used in fuel blending applications.

5 Marks Q25. Explain the conversion of ethanol into ethanoic acid.

Ethanol undergoes oxidation in the presence of suitable oxidising agents such as KMnO₄ or K₂Cr₂O₇.

CH₃CH₂OH + 2[O] → CH₃COOH + H₂O

Thus ethanol is converted into ethanoic acid.

6 Marks Q26. Explain all important chemical reactions of ethanol with balanced equations.

1. Reaction with Sodium:
2C₂H₅OH + 2Na → 2C₂H₅ONa + H₂

2. Oxidation:
CH₃CH₂OH + 2[O] → CH₃COOH + H₂O

3. Dehydration:
C₂H₅OH → C₂H₄ + H₂O

4. Combustion:
C₂H₅OH + 3O₂ → 2CO₂ + 3H₂O + Heat

6 Marks Q27. Explain the preparation of ethene from ethanol.

Ethanol is heated with concentrated sulphuric acid at about 443 K. The sulphuric acid helps remove water from ethanol.

C₂H₅OH   conc. H₂SO₄, 443 K   → C₂H₄ + H₂O

The reaction is called dehydration or elimination reaction.

6 Marks Q28. Write a detailed note on the uses of ethanol.

Ethanol is used:

1. Solvent: Used in medicines, perfumes and laboratory preparations.

2. Fuel: It burns readily and releases heat.

3. Fuel blending: It can be blended with petrol for fuel applications.

4. Pharmaceutical industry: Used as a solvent and processing ingredient.

5. Cosmetics and perfumes: Used as a solvent in several products.

6 Marks Q29. Compare ethanol's reactions with sodium, oxidation and dehydration.

Reaction	Condition	Product
With Sodium	Na metal	Sodium ethoxide + H₂
Oxidation	KMnO₄/K₂Cr₂O₇	Ethanoic acid
Dehydration	Conc. H₂SO₄, 443 K	Ethene + H₂O

6 Marks Q30. Prepare a complete reaction map of ethanol.

ETHANOL – C₂H₅OH

↓

🔥 COMBUSTION
C₂H₅OH + 3O₂
↓
2CO₂ + 3H₂O + Heat

↓

🧪 OXIDATION
Ethanol
↓
Ethanoic Acid

↓

⚗️ WITH SODIUM
Ethanol + Na
↓
Sodium Ethoxide + H₂

↓

💧 DEHYDRATION
Ethanol
↓
Ethene + H₂O

16. Quick Revision – त्वरित पुनरावृत्ति

• Formula: C₂H₅OH
• Structure: CH₃–CH₂–OH
• Functional Group: –OH
• Family: Alcohol
• Oxidation: Ethanol → Ethanoic acid
• With Sodium: Sodium ethoxide + Hydrogen
• Dehydration: Ethanol → Ethene + Water
• Combustion: Ethanol → CO₂ + H₂O + Heat
• Catalyst/Condition for dehydration: Concentrated H₂SO₄, about 443 K
• Important uses: Solvent, fuel, pharmaceutical preparations, perfumes and cosmetics

⭐ EXAM MEMORY TRICK

ETHANOL = C₂H₅OH

🔥 Burn → CO₂ + H₂O + Heat

🧪 Oxidation → Ethanoic Acid

⚗️ Na → Sodium Ethoxide + H₂

💧 Dehydration → Ethene + H₂O

443 K + Conc. H₂SO₄ → Ethene

Class 10th Science Chapter 4 – Carbon and Its Compounds | Combustion, Oxidation, Addition and Substitution Reactions

Carbon and Its Compounds

Combustion, Oxidation, Addition and Substitution Reactions

दहन, ऑक्सीकरण, योग एवं प्रतिस्थापन अभिक्रियाएँ

Class 10 Science | CBSE + Foundation + Competitive

Carbon and Its Compounds | Chemical Reactions

1. Chemical Properties of Carbon Compounds – रासायनिक गुण

English:
Carbon compounds undergo different chemical reactions depending upon their structure, functional group and type of carbon-carbon bond. The four important reactions studied in Class 10 are:

1. Combustion Reaction
2. Oxidation Reaction
3. Addition Reaction
4. Substitution Reaction

हिन्दी:
कार्बन यौगिक अपनी संरचना, क्रियात्मक समूह तथा कार्बन-कार्बन बंध के प्रकार के आधार पर विभिन्न रासायनिक अभिक्रियाएँ करते हैं। कक्षा 10 में मुख्य रूप से चार अभिक्रियाएँ महत्वपूर्ण हैं:

1. दहन अभिक्रिया
2. ऑक्सीकरण अभिक्रिया
3. योग अभिक्रिया
4. प्रतिस्थापन अभिक्रिया

Memory Trick – याद रखने की ट्रिक:

🔥 C = Combustion
🧪 O = Oxidation
➕ A = Addition
🔄 S = Substitution

C → O → A → S

2. Combustion Reaction – दहन अभिक्रिया

English:
Combustion is a chemical reaction in which a carbon compound reacts with oxygen and produces heat and usually light. Most carbon compounds burn in oxygen to form carbon dioxide, water and heat.

हिन्दी:
दहन वह रासायनिक अभिक्रिया है जिसमें कार्बन यौगिक ऑक्सीजन के साथ अभिक्रिया करके कार्बन डाइऑक्साइड, जल तथा ऊष्मा उत्पन्न करता है।

CH₄ + 2O₂ → CO₂ + 2H₂O + Heat

Example: Combustion of Methane

मीथेन ऑक्सीजन में जलकर कार्बन डाइऑक्साइड और जल बनाता है।

CH₄ + 2O₂ → CO₂ + 2H₂O + Heat

Combustion of Ethanol – एथेनॉल का दहन:

C₂H₅OH + 3O₂ → 2CO₂ + 3H₂O + Heat

Important:
Many carbon compounds are used as fuels because their combustion releases a large amount of heat.

महत्वपूर्ण:
कई कार्बन यौगिक ईंधन के रूप में उपयोग किए जाते हैं क्योंकि उनके दहन से काफी मात्रा में ऊष्मा प्राप्त होती है।

3. Incomplete Combustion – अपूर्ण दहन

English:
When sufficient oxygen is not available, carbon compounds may undergo incomplete combustion. It may produce carbon monoxide (CO) and/or carbon (soot) instead of only carbon dioxide.

हिन्दी:
जब पर्याप्त ऑक्सीजन उपलब्ध नहीं होती है तब कार्बन यौगिकों का अपूर्ण दहन हो सकता है। इसमें कार्बन डाइऑक्साइड के साथ या उसके स्थान पर कार्बन मोनोऑक्साइड तथा कार्बन (कालिख) बन सकता है।

2CH₄ + 3O₂ → 2CO + 4H₂O

CH₄ + O₂ → C + 2H₂O

Safety Point: Carbon monoxide (CO) is a poisonous gas.
कार्बन मोनोऑक्साइड एक विषैली गैस है।

4. Oxidation Reaction – ऑक्सीकरण अभिक्रिया

English:
Oxidation can be understood as addition of oxygen or removal of hydrogen from a substance. In carbon compounds, ethanol can be oxidised to ethanoic acid.

हिन्दी:
ऑक्सीकरण को किसी पदार्थ में ऑक्सीजन के जुड़ने या हाइड्रोजन के हटने की प्रक्रिया के रूप में समझा जा सकता है। कार्बन यौगिकों में एथेनॉल का ऑक्सीकरण करके एथेनोइक अम्ल प्राप्त किया जा सकता है।

CH₃CH₂OH + 2[O] → CH₃COOH + H₂O

Ethanol → Oxidation → Ethanoic Acid

एथेनॉल → ऑक्सीकरण → एथेनोइक अम्ल

Oxidising Agents – ऑक्सीकारक:

• Alkaline potassium permanganate – KMnO₄
• Acidified potassium dichromate – K₂Cr₂O₇

Exam Point:
KMnO₄ और K₂Cr₂O₇ का उपयोग कार्बनिक यौगिकों के ऑक्सीकरण के लिए किया जा सकता है।

5. Addition Reaction – योग अभिक्रिया

English:
Addition reactions are generally shown by unsaturated carbon compounds containing double or triple bonds. In this reaction, atoms or groups are added across a multiple bond.

हिन्दी:
योग अभिक्रिया सामान्यतः उन असंतृप्त कार्बन यौगिकों में होती है जिनमें द्विबंध या त्रिबंध उपस्थित होता है। इस अभिक्रिया में बहु-बंध पर परमाणु या समूह जुड़ते हैं।

CH₂=CH₂ + H₂ → CH₃–CH₃

Ethene + Hydrogen → Ethane

एथीन + हाइड्रोजन → एथेन

यह एक addition reaction है क्योंकि एथीन के C=C बंध पर हाइड्रोजन जुड़ता है।

6. Hydrogenation – हाइड्रोजनीकरण

Hydrogenation is the addition of hydrogen to an unsaturated compound in the presence of a catalyst.

असंतृप्त यौगिक में उत्प्रेरक की उपस्थिति में हाइड्रोजन जोड़ने की प्रक्रिया को हाइड्रोजनीकरण कहते हैं।

CH₂=CH₂ + H₂   Ni   → CH₃–CH₃

Catalyst – उत्प्रेरक:
Nickel (Ni)

Example:
Vegetable oils → Hydrogenation → More saturated products

वनस्पति तेल → हाइड्रोजनीकरण → अधिक संतृप्त उत्पाद

Industrial Application:
Hydrogenation is used in the processing of vegetable oils to produce more saturated products such as vanaspati.

7. Substitution Reaction – प्रतिस्थापन अभिक्रिया

English:
Substitution reaction is a reaction in which one atom or group of atoms in a molecule is replaced by another atom or group. Saturated hydrocarbons commonly undergo substitution reactions.

हिन्दी:
प्रतिस्थापन अभिक्रिया वह अभिक्रिया है जिसमें किसी अणु का एक परमाणु या परमाणुओं का समूह दूसरे परमाणु या समूह द्वारा प्रतिस्थापित हो जाता है। संतृप्त हाइड्रोकार्बन सामान्यतः प्रतिस्थापन अभिक्रियाएँ करते हैं।

CH₄ + Cl₂   Sunlight   → CH₃Cl + HCl

Explanation – व्याख्या:

मीथेन में उपस्थित एक हाइड्रोजन परमाणु को क्लोरीन परमाणु प्रतिस्थापित कर देता है।

इसलिए यह substitution reaction है।

8. Chlorination of Methane – मीथेन का क्लोरीनीकरण

Methane reacts with chlorine in the presence of sunlight or ultraviolet light.

मीथेन सूर्य के प्रकाश या UV प्रकाश की उपस्थिति में क्लोरीन के साथ अभिक्रिया करता है।

CH₄ + Cl₂ → CH₃Cl + HCl

Further substitution can occur:

CH₃Cl + Cl₂ → CH₂Cl₂ + HCl
CH₂Cl₂ + Cl₂ → CHCl₃ + HCl
CHCl₃ + Cl₂ → CCl₄ + HCl

Remember:
Methane + Chlorine + Sunlight → Substitution Reaction

9. Addition vs Substitution – योग एवं प्रतिस्थापन में अंतर

Basis	Addition Reaction	Substitution Reaction
Usually occurs in	Unsaturated compounds	Saturated compounds
Bond	Double/Triple bond	Single bonds
Process	Atoms/groups are added	One atom/group replaces another
Example	Ethene + H₂ → Ethane	Methane + Cl₂ → CH₃Cl + HCl

10. Reaction Summary – अभिक्रियाओं का सार

Reaction	Reactant	Product
Combustion	Carbon compound + O₂	CO₂ + H₂O + Heat
Oxidation	Ethanol + [O]	Ethanoic acid
Addition	Ethene + H₂	Ethane
Substitution	Methane + Cl₂	Chloromethane + HCl

11. 30 MCQs – बहुविकल्पीय प्रश्न

Q1. Complete combustion of methane produces:

A) CO + H₂O

B) CO₂ + H₂O

C) C + H₂

D) CH₃Cl

Answer: B) CO₂ + H₂O

Q2. Which reaction is characteristic of unsaturated compounds?

A) Addition

B) Substitution

C) Neutralisation

D) Precipitation

Answer: A) Addition

Q3. Ethanol on oxidation gives:

A) Ethane

B) Methane

C) Ethanoic acid

D) Ethene

Answer: C) Ethanoic acid

Q4. Nickel is used as a catalyst in:

A) Combustion

B) Substitution

C) Neutralisation

D) Hydrogenation

Answer: D) Hydrogenation

Q5. Methane reacts with chlorine in the presence of:

A) Sunlight

B) Water

C) NaOH

D) CO₂

Answer: A) Sunlight

Q6. Which compound contains a double bond?

A) Methane

B) Ethene

C) Ethane

D) Propane

Answer: B) Ethene

Q7. The formula of ethene is:

A) C₂H₆

B) C₂H₂

C) C₂H₄

D) CH₄

Answer: C) C₂H₄

Q8. Which is a poisonous gas produced during incomplete combustion?

A) O₂

B) N₂

C) CO₂

D) CO

Answer: D) CO

Q9. Hydrogenation converts an unsaturated compound into a:

A) More saturated compound

B) More ionic compound

C) Metal

D) Salt

Answer: A) More saturated compound

Q10. Which reaction occurs in methane chlorination?

A) Addition

B) Substitution

C) Oxidation only

D) Neutralisation

Answer: B) Substitution

Q11. Which substance is an oxidising agent?

A) KMnO₄

B) NaCl

C) CH₄

D) H₂

Answer: A) KMnO₄

Q12. Ethene + H₂ gives:

A) Ethanol

B) Ethanoic acid

C) Ethane

D) Methane

Answer: C) Ethane

Q13. Saturated hydrocarbons generally undergo:

A) Addition

B) Substitution

C) Hydrolysis

D) Neutralisation

Answer: B) Substitution

Q14. Which gas is formed during complete combustion?

A) CO₂

B) CO

C) H₂

D) N₂

Answer: A) CO₂

Q15. Oxidation of ethanol produces:

A) Ethyne

B) Methane

C) Ethanoic acid

D) Ethane

Answer: C) Ethanoic acid

Q16. Which catalyst is commonly used in hydrogenation?

A) Cu

B) Fe

C) Zn

D) Ni

Answer: D) Ni

Q17. A reaction involving addition across C=C is:

A) Addition

B) Substitution

C) Neutralisation

D) Decomposition

Answer: A) Addition

Q18. Methane is:

A) Unsaturated

B) Saturated

C) Aromatic only

D) Ionic

Answer: B) Saturated

Q19. Which reaction releases heat?

A) Combustion

B) Addition only

C) Substitution only

D) Hydrolysis only

Answer: A) Combustion

Q20. The product of CH₄ + Cl₂ in sunlight is:

A) C₂H₆

B) CH₃Cl + HCl

C) CO₂

D) CH₃OH

Answer: B) CH₃Cl + HCl

Q21. Incomplete combustion may produce:

A) Only oxygen

B) Only nitrogen

C) Carbon monoxide

D) Hydrogen chloride only

Answer: C) Carbon monoxide

Q22. Which compound is unsaturated?

A) C₂H₄

B) C₂H₆

C) CH₄

D) C₃H₈

Answer: A) C₂H₄

Q23. Hydrogenation requires:

A) Chlorine

B) Hydrogen

C) Oxygen only

D) Nitrogen

Answer: B) Hydrogen

Q24. Which one is an oxidising agent?

A) KMnO₄

B) CH₄

C) C₂H₆

D) H₂

Answer: A) KMnO₄

Q25. Substitution means:

A) Addition of oxygen

B) Removal of carbon

C) Replacement of an atom/group

D) Formation of water only

Answer: C) Replacement of an atom/group

Q26. Which reaction is used in processing vegetable oils?

A) Hydrogenation

B) Neutralisation

C) Precipitation

D) Electrolysis

Answer: A) Hydrogenation

Q27. Which compound is saturated?

A) Ethene

B) Ethyne

C) Ethane

D) Propene

Answer: C) Ethane

Q28. What is required for chlorination of methane?

A) Sunlight/UV light

B) Nickel only

C) Water only

D) NaCl only

Answer: A) Sunlight/UV light

Q29. Ethanol is oxidised to:

A) Ethane

B) Ethanoic acid

C) Methane

D) Ethyne

Answer: B) Ethanoic acid

Q30. Which sequence is correct?

A) Unsaturated → Addition

B) Saturated → Addition only

C) Ethanol → Methane by oxidation

D) Methane + Cl₂ → Addition

Answer: A) Unsaturated → Addition

12. 30 Subjective Questions – वर्णनात्मक प्रश्न

1 Mark Q1. What is combustion?
दहन क्या है?

Answer: Combustion is the reaction of a substance with oxygen producing heat and usually light.

ऑक्सीजन के साथ अभिक्रिया जिसमें ऊष्मा तथा सामान्यतः प्रकाश उत्पन्न होता है, दहन कहलाती है।

1 Mark Q2. Name the gas formed during complete combustion of carbon compounds.

Answer: Carbon dioxide (CO₂).

1 Mark Q3. Name the catalyst used in hydrogenation.

Answer: Nickel (Ni).

1 Mark Q4. Which reaction is characteristic of unsaturated compounds?

Answer: Addition reaction.

1 Mark Q5. What is the product of oxidation of ethanol?

Answer: Ethanoic acid.

2 Marks Q6. Write the combustion equation of methane.

Solution:

CH₄ + 2O₂ → CO₂ + 2H₂O + Heat

2 Marks Q7. What is an addition reaction?

Answer:
An addition reaction is a reaction in which atoms or groups are added across a multiple bond.

Example: CH₂=CH₂ + H₂ → CH₃CH₃

2 Marks Q8. What is substitution reaction?

Answer:
A reaction in which one atom or group is replaced by another atom or group is called substitution reaction.

CH₄ + Cl₂ → CH₃Cl + HCl

2 Marks Q9. What is hydrogenation?

Answer:
Addition of hydrogen to an unsaturated compound in the presence of a catalyst is called hydrogenation.

2 Marks Q10. What happens during incomplete combustion?

Answer:
When oxygen is insufficient, carbon compounds may undergo incomplete combustion and form CO and/or carbon.

3 Marks Q11. Explain combustion of carbon compounds with an example.

Answer:

• Carbon compounds react with oxygen.
• Heat and usually light are produced.
• Complete combustion generally gives CO₂ and H₂O.

Example: CH₄ + 2O₂ → CO₂ + 2H₂O + Heat

3 Marks Q12. Explain oxidation of ethanol.

Answer:
Ethanol is oxidised using an oxidising agent such as KMnO₄ or K₂Cr₂O₇.

CH₃CH₂OH + 2[O] → CH₃COOH + H₂O

Thus ethanol changes into ethanoic acid.

3 Marks Q13. Explain addition reaction with an example.

Answer:
Unsaturated compounds containing double or triple bonds undergo addition reactions.

CH₂=CH₂ + H₂ → CH₃CH₃

Ethene changes into ethane.

3 Marks Q14. Explain substitution reaction of methane.

Answer:
Methane reacts with chlorine in the presence of sunlight.

CH₄ + Cl₂ → CH₃Cl + HCl

One hydrogen atom of methane is replaced by chlorine.

3 Marks Q15. Why is nickel used in hydrogenation?

Answer:
Nickel acts as a catalyst. It helps hydrogen add to the multiple bond of an unsaturated compound and increases the rate of reaction.

4 Marks Q16. Differentiate between addition and substitution reactions.

Addition	Substitution
Usually unsaturated compounds	Usually saturated compounds
Atoms/groups are added	One atom/group replaces another
Example: Ethene + H₂	Example: Methane + Cl₂

4 Marks Q17. Explain complete and incomplete combustion.

Complete combustion:
Occurs in sufficient oxygen and generally produces CO₂, H₂O and heat.

Incomplete combustion:
Occurs when oxygen is insufficient and may produce CO and/or carbon.

4 Marks Q18. Write four major chemical reactions of carbon compounds.

1. Combustion
2. Oxidation
3. Addition
4. Substitution

4 Marks Q19. Explain hydrogenation of vegetable oils.

Answer:
Vegetable oils contain unsaturated compounds. Hydrogen is added to their multiple bonds in the presence of nickel catalyst. This increases saturation and is used in the processing of vegetable oils.

4 Marks Q20. Write the chemical equation for chlorination of methane and explain it.

CH₄ + Cl₂   Sunlight   → CH₃Cl + HCl

One hydrogen atom of methane is replaced by chlorine. Therefore, it is a substitution reaction.

5 Marks Q21. Explain the four major chemical properties of carbon compounds with equations.

1. Combustion:
CH₄ + 2O₂ → CO₂ + 2H₂O + Heat

2. Oxidation:
CH₃CH₂OH + 2[O] → CH₃COOH + H₂O

3. Addition:
CH₂=CH₂ + H₂ → CH₃CH₃

4. Substitution:
CH₄ + Cl₂ → CH₃Cl + HCl

5 Marks Q22. Explain why carbon compounds are used as fuels.

Many carbon compounds undergo combustion and release considerable heat energy.

For example: CH₄ + 2O₂ → CO₂ + 2H₂O + Heat

Therefore hydrocarbons and several other carbon compounds are widely used as fuels.

5 Marks Q23. Explain the oxidation of ethanol in detail.

Ethanol reacts with an oxidising agent such as alkaline KMnO₄ or acidified K₂Cr₂O₇.

CH₃CH₂OH + 2[O] → CH₃COOH + H₂O

The alcohol group is converted into the carboxylic acid functional group, producing ethanoic acid.

5 Marks Q24. Explain the addition reaction of ethene with hydrogen.

Ethene contains a carbon-carbon double bond. Hydrogen adds across this double bond in the presence of nickel catalyst.

CH₂=CH₂ + H₂   Ni   → CH₃–CH₃

Ethene is converted into ethane.

5 Marks Q25. Explain substitution reaction with methane as an example.

Methane is a saturated hydrocarbon. In the presence of sunlight/UV light, chlorine replaces hydrogen atoms of methane.

CH₄ + Cl₂ → CH₃Cl + HCl

Further substitution can produce CH₂Cl₂, CHCl₃ and CCl₄.

6 Marks Q26. Describe combustion and incomplete combustion of carbon compounds.

Complete Combustion:
When sufficient oxygen is available, carbon compounds burn completely.
CH₄ + 2O₂ → CO₂ + 2H₂O + Heat

Incomplete Combustion:
When oxygen is insufficient, incomplete combustion occurs.
2CH₄ + 3O₂ → 2CO + 4H₂O

It may also produce carbon/soot.

6 Marks Q27. Explain addition and hydrogenation reactions with suitable examples.

Unsaturated compounds undergo addition reactions.

CH₂=CH₂ + H₂ → CH₃CH₃

The addition of hydrogen to an unsaturated compound in the presence of nickel catalyst is called hydrogenation.

Hydrogenation is used in the processing of vegetable oils to make more saturated products.

6 Marks Q28. Explain the chlorination of methane step by step.

Methane reacts with chlorine in sunlight.

Step 1: CH₄ + Cl₂ → CH₃Cl + HCl

Step 2: CH₃Cl + Cl₂ → CH₂Cl₂ + HCl

Step 3: CH₂Cl₂ + Cl₂ → CHCl₃ + HCl

Step 4: CHCl₃ + Cl₂ → CCl₄ + HCl

This is a substitution reaction.

6 Marks Q29. Compare combustion, oxidation, addition and substitution reactions.

Reaction	Main Feature	Example
Combustion	Reaction with oxygen	CH₄ + O₂
Oxidation	Addition of oxygen/removal of hydrogen	Ethanol → Ethanoic acid
Addition	Addition across multiple bond	Ethene + H₂ → Ethane
Substitution	Replacement of atom/group	Methane + Cl₂

6 Marks Q30. Prepare a complete reaction map of carbon compounds.

CARBON COMPOUNDS

↓

🔥 COMBUSTION
Carbon compound + O₂
↓
CO₂ + H₂O + Heat

↓

🧪 OXIDATION
Ethanol
↓
Ethanoic Acid

↓

➕ ADDITION
Ethene + H₂
↓
Ethane

↓

🔄 SUBSTITUTION
Methane + Cl₂
↓
Chloromethane + HCl

13. Quick Revision – त्वरित पुनरावृत्ति

• Combustion: Carbon compound + O₂ → CO₂ + H₂O + Heat
• Incomplete Combustion: CO and/or carbon may be formed.
• Oxidation: Ethanol → Ethanoic acid
• Addition: Usually occurs in unsaturated compounds.
• Hydrogenation: Addition of H₂ to an unsaturated compound.
• Catalyst: Nickel (Ni)
• Substitution: Usually occurs in saturated hydrocarbons.
• Methane Chlorination: CH₄ + Cl₂ → CH₃Cl + HCl

⭐ ONE-LINE EXAM REVISION

🔥 Combustion: Carbon compound + O₂ → CO₂ + H₂O + Heat

🧪 Oxidation: Ethanol → Ethanoic Acid

➕ Addition: Unsaturated + H₂ → Saturated

🔄 Substitution: CH₄ + Cl₂ → CH₃Cl + HCl

Remember:
Unsaturated → Addition
Saturated → Substitution

Class 10th Science Chapter 4 – Carbon and Its Compounds | Chemical Properties of Carbon Compounds

Carbon and Its Compounds

Chemical Properties of Carbon Compounds | कार्बन यौगिकों के रासायनिक गुण

Class 10 Science | CBSE + Foundation + Competitive

Chemical Properties of Carbon Compounds | कार्बन यौगिकों के रासायनिक गुण

1. Introduction – परिचय

English:
Carbon compounds mainly contain carbon atoms bonded with hydrogen, oxygen, nitrogen, sulphur, halogens and other elements. Their chemical properties depend upon the functional group, type of carbon-carbon bond and structure of the molecule.

हिन्दी:
कार्बन यौगिकों में मुख्यतः कार्बन परमाणु हाइड्रोजन, ऑक्सीजन, नाइट्रोजन, सल्फर, हैलोजन आदि तत्वों से बंधे होते हैं। इनके रासायनिक गुण मुख्य रूप से उपस्थित क्रियात्मक समूह, कार्बन-कार्बन बंध के प्रकार तथा अणु की संरचना पर निर्भर करते हैं।

Important Chemical Reactions:
1. Combustion – दहन
2. Oxidation – ऑक्सीकरण
3. Addition Reaction – योग अभिक्रिया
4. Substitution Reaction – प्रतिस्थापन अभिक्रिया

2. Combustion of Carbon Compounds – कार्बन यौगिकों का दहन

English:
Combustion is a chemical reaction in which a substance reacts with oxygen and produces heat and usually light. Carbon compounds generally burn in oxygen to form carbon dioxide and water along with heat and light.

हिन्दी:
दहन वह रासायनिक अभिक्रिया है जिसमें कोई पदार्थ ऑक्सीजन के साथ अभिक्रिया करके ऊष्मा तथा सामान्यतः प्रकाश उत्पन्न करता है। कार्बन यौगिक सामान्यतः ऑक्सीजन में जलकर कार्बन डाइऑक्साइड, जल तथा ऊष्मा उत्पन्न करते हैं।

CH₄ + 2O₂ → CO₂ + 2H₂O + Heat

Example – Ethanol:

C₂H₅OH + 3O₂ → 2CO₂ + 3H₂O + Heat

Observation – अवलोकन:

• Many carbon compounds burn with a flame.
• कार्बन यौगिक प्रायः ज्वाला के साथ जलते हैं।
• Complete combustion usually produces CO₂ and H₂O.
• पूर्ण दहन में सामान्यतः CO₂ और H₂O बनते हैं।

Exam Point:
Saturated hydrocarbons generally burn with a clean flame, whereas many unsaturated hydrocarbons burn with a yellow, sooty flame due to incomplete combustion.

3. Incomplete Combustion – अपूर्ण दहन

English:
When oxygen is insufficient, carbon compounds may undergo incomplete combustion. Carbon monoxide and/or carbon may be formed along with water.

हिन्दी:
जब ऑक्सीजन की मात्रा पर्याप्त नहीं होती है तब कार्बन यौगिकों का अपूर्ण दहन हो सकता है। इसमें कार्बन मोनोऑक्साइड तथा कभी-कभी कार्बन (कालिख) बन सकती है।

2CH₄ + 3O₂ → 2CO + 4H₂O

CH₄ + O₂ → C + 2H₂O

Safety: Carbon monoxide (CO) is a poisonous gas because it reduces the oxygen-carrying capacity of blood.

4. Oxidation of Carbon Compounds – कार्बन यौगिकों का ऑक्सीकरण

English:
Oxidation is a reaction in which oxygen is added to a substance or hydrogen is removed from it. In Class 10 carbon chemistry, ethanol can be oxidised to ethanoic acid using alkaline KMnO₄ or acidified K₂Cr₂O₇.

हिन्दी:
ऑक्सीकरण वह अभिक्रिया है जिसमें किसी पदार्थ में ऑक्सीजन जुड़ती है या हाइड्रोजन निकलता है। कक्षा 10 कार्बन रसायन में एथेनॉल का ऑक्सीकरण करके एथेनोइक अम्ल बनाया जा सकता है।

CH₃CH₂OH + 2[O] → CH₃COOH + H₂O

Oxidising Agents – ऑक्सीकारक:

• Alkaline potassium permanganate (KMnO₄)
• Acidified potassium dichromate (K₂Cr₂O₇)

याद रखें:

Ethanol → Oxidation → Ethanoic Acid
एथेनॉल → ऑक्सीकरण → एथेनोइक अम्ल

5. Addition Reaction – योग अभिक्रिया

English:
Addition reactions are characteristic of unsaturated carbon compounds containing double or triple bonds. During an addition reaction, atoms or groups are added across the multiple bond.

हिन्दी:
योग अभिक्रिया मुख्यतः असंतृप्त कार्बन यौगिकों में होती है, जिनमें द्विबंध या त्रिबंध उपस्थित होता है। इस अभिक्रिया में बहु-बंध के स्थान पर नए परमाणु या समूह जुड़ते हैं।

CH₂=CH₂ + H₂ → CH₃–CH₃

Ethene + Hydrogen → Ethane
एथीन + हाइड्रोजन → एथेन

Hydrogenation – हाइड्रोजनीकरण:
The addition of hydrogen to an unsaturated compound in the presence of a catalyst such as nickel is called hydrogenation.

असंतृप्त यौगिक में निकेल जैसे उत्प्रेरक की उपस्थिति में हाइड्रोजन जोड़ने की प्रक्रिया को हाइड्रोजनीकरण कहते हैं।

CH₂=CH₂ + H₂   Ni   → CH₃–CH₃

6. Hydrogenation of Vegetable Oils – वनस्पति तेलों का हाइड्रोजनीकरण

English:
Vegetable oils generally contain unsaturated compounds. Hydrogenation converts some unsaturated compounds into more saturated compounds. This process is used in the manufacture of vanaspati ghee from vegetable oils.

हिन्दी:
वनस्पति तेलों में सामान्यतः असंतृप्त यौगिक पाए जाते हैं। हाइड्रोजनीकरण द्वारा कुछ असंतृप्त यौगिकों को अधिक संतृप्त यौगिकों में बदला जाता है। इस प्रक्रिया का उपयोग वनस्पति तेलों से वनस्पति घी बनाने में किया जाता है।

Unsaturated Oil + H₂ → Saturated/More Saturated Product
Catalyst: Ni

Important: Nickel acts as a catalyst. It increases the rate of hydrogenation without being consumed overall in the reaction.

7. Substitution Reaction – प्रतिस्थापन अभिक्रिया

English:
Saturated hydrocarbons generally undergo substitution reactions. In these reactions, one atom or group in a molecule is replaced by another atom or group.

हिन्दी:
संतृप्त हाइड्रोकार्बन सामान्यतः प्रतिस्थापन अभिक्रियाएँ करते हैं। इस अभिक्रिया में अणु के एक परमाणु या समूह का स्थान दूसरा परमाणु या समूह ले लेता है।

CH₄ + Cl₂   Sunlight   → CH₃Cl + HCl

Stepwise Chlorination of Methane:

1. CH₄ + Cl₂ → CH₃Cl + HCl
2. CH₃Cl + Cl₂ → CH₂Cl₂ + HCl
3. CH₂Cl₂ + Cl₂ → CHCl₃ + HCl
4. CHCl₃ + Cl₂ → CCl₄ + HCl

हिन्दी: मीथेन में क्लोरीन परमाणु क्रमशः हाइड्रोजन का स्थान ले सकता है।

Exam Point: Sunlight/UV light is required to initiate the chlorination of methane.

8. Saturated vs Unsaturated Compounds – संतृप्त एवं असंतृप्त यौगिक

Property	Saturated	Unsaturated
Carbon-carbon bond	Only single bonds	Double or triple bond present
Typical reaction	Substitution	Addition
Example	Ethane, C₂H₆	Ethene, C₂H₄
Hydrogenation	Already relatively hydrogen-rich	Can add H₂ across multiple bond

9. Important Chemical Reactions – महत्वपूर्ण अभिक्रियाएँ

Reaction	Example	Main Product
Combustion	CH₄ + O₂	CO₂ + H₂O
Oxidation	Ethanol + [O]	Ethanoic acid
Addition	Ethene + H₂	Ethane
Substitution	Methane + Cl₂	Chloromethane + HCl

10. Functional Groups and Chemical Properties

English:
The functional group largely determines the characteristic chemical reactions of an organic compound.

हिन्दी:
क्रियात्मक समूह किसी कार्बनिक यौगिक की विशिष्ट रासायनिक अभिक्रियाओं को काफी हद तक निर्धारित करता है।

Functional Group	Name	Example
–OH	Alcohol	CH₃CH₂OH
–CHO	Aldehyde	CH₃CHO
>C=O	Ketone	CH₃COCH₃
–COOH	Carboxylic Acid	CH₃COOH
–Cl, –Br	Halo group	CH₃Cl

11. Addition vs Substitution – योग एवं प्रतिस्थापन में अंतर

Point	Addition	Substitution
Usually occurs in	Unsaturated compounds	Saturated compounds
Basic change	Atoms/groups add across multiple bond	One atom/group replaces another
Example	CH₂=CH₂ + H₂ → CH₃CH₃	CH₄ + Cl₂ → CH₃Cl + HCl
Typical condition	Catalyst may be required	Light/heat may initiate reaction

12. 30 MCQs – बहुविकल्पीय प्रश्न

Q1. Which gas is generally produced during complete combustion of carbon compounds?

A) Oxygen

B) Carbon dioxide

C) Nitrogen

D) Hydrogen

Answer: B) Carbon dioxide

Q2. Complete combustion of methane produces:

A) CO + H₂

B) C + H₂

C) CO₂ + H₂O

D) CH₃OH

Answer: C) CO₂ + H₂O

Q3. Which reaction is characteristic of unsaturated hydrocarbons?

A) Addition

B) Neutralisation

C) Precipitation

D) Decomposition

Answer: A) Addition

Q4. Which catalyst is commonly used in hydrogenation of vegetable oils?

A) Fe

B) Cu

C) Zn

D) Ni

Answer: D) Ni

Q5. Ethene reacts with hydrogen to form:

A) Ethane

B) Ethyne

C) Ethanol

D) Ethanoic acid

Answer: A) Ethane

Q6. Which reaction occurs when hydrogen is added to an unsaturated compound?

A) Substitution

B) Addition

C) Oxidation only

D) Neutralisation

Answer: B) Addition

Q7. Ethanol can be oxidised to:

A) Methane

B) Ethene

C) Ethanoic acid

D) Ethyne

Answer: C) Ethanoic acid

Q8. Which compound generally undergoes substitution reaction?

A) Ethene

B) Ethyne

C) Benzene only

D) Methane

Answer: D) Methane

Q9. Methane reacts with chlorine in the presence of:

A) Sunlight/UV light

B) Water

C) NaOH only

D) CO₂

Answer: A) Sunlight/UV light

Q10. In incomplete combustion, which poisonous gas may be formed?

A) CO₂

B) CO

C) O₂

D) H₂

Answer: B) CO

Q11. Which compound contains a double bond?

A) Ethane

B) Methane

C) Ethene

D) Propane

Answer: C) Ethene

Q12. The formula of ethene is:

A) C₂H₆

B) C₂H₄

C) C₂H₂

D) CH₄

Answer: B) C₂H₄

Q13. Which substance acts as an oxidising agent?

A) KMnO₄

B) NaCl

C) CH₄

D) H₂

Answer: A) KMnO₄

Q14. Oxidation of ethanol gives:

A) Ethane

B) Ethyne

C) Methane

D) Ethanoic acid

Answer: D) Ethanoic acid

Q15. Which type of bond is present in saturated hydrocarbons?

A) Triple only

B) Single only

C) Double only

D) Ionic

Answer: B) Single only

Q16. Which compound can undergo hydrogenation?

A) Ethane

B) Methane

C) Ethene

D) Propane

Answer: C) Ethene

Q17. Hydrogenation of vegetable oils generally makes them:

A) More saturated

B) More acidic

C) More ionic

D) More oxidised

Answer: A) More saturated

Q18. The functional group –OH represents:

A) Aldehyde

B) Ketone

C) Carboxylic acid

D) Alcohol

Answer: D) Alcohol

Q19. The functional group –COOH represents:

A) Alcohol

B) Carboxylic acid

C) Aldehyde

D) Halo group

Answer: B) Carboxylic acid

Q20. Which of the following is a saturated hydrocarbon?

A) C₂H₄

B) C₂H₂

C) C₂H₆

D) C₃H₄

Answer: C) C₂H₆

Q21. Which reaction replaces hydrogen in methane by chlorine?

A) Substitution

B) Addition

C) Oxidation

D) Reduction

Answer: A) Substitution

Q22. Which reaction converts ethene into ethane?

A) Oxidation

B) Substitution

C) Combustion

D) Hydrogenation

Answer: D) Hydrogenation

Q23. Which gas can cause poisoning during incomplete combustion?

A) CO

B) O₂

C) N₂

D) CO₂ only

Answer: A) CO

Q24. A yellow sooty flame is commonly associated with:

A) Complete combustion

B) Incomplete combustion

C) Neutralisation

D) Electrolysis

Answer: B) Incomplete combustion

Q25. Which compound is an unsaturated hydrocarbon?

A) C₃H₈

B) C₄H₁₀

C) C₂H₆

D) C₂H₄

Answer: D) C₂H₄

Q26. The oxidation of ethanol involves:

A) Addition of oxygen

B) Removal of carbon

C) Formation of methane

D) Formation of ethene only

Answer: A) Addition of oxygen

Q27. Which compound contains a triple bond?

A) Ethane

B) Ethene

C) Ethyne

D) Methane

Answer: C) Ethyne

Q28. The catalyst used in hydrogenation is:

A) Nickel

B) Sodium chloride

C) Calcium carbonate

D) Hydrochloric acid

Answer: A) Nickel

Q29. Which reaction is represented by CH₄ + Cl₂ → CH₃Cl + HCl?

A) Addition

B) Substitution

C) Combustion

D) Neutralisation

Answer: B) Substitution

Q30. Which statement is correct?

A) Saturated hydrocarbons generally undergo addition

B) Unsaturated hydrocarbons cannot react

C) Saturated hydrocarbons generally undergo substitution

D) Hydrogenation removes hydrogen

Answer: C) Saturated hydrocarbons generally undergo substitution

13. 30 Subjective Questions – वर्णनात्मक प्रश्न

1 Mark Q1. What is combustion?
दहन क्या है?

Answer: Combustion is the reaction of a substance with oxygen producing heat and usually light.
दहन ऑक्सीजन के साथ अभिक्रिया है जिसमें ऊष्मा तथा सामान्यतः प्रकाश उत्पन्न होता है।

1 Mark Q2. Name the gas formed during complete combustion of carbon compounds.

Answer: Carbon dioxide (CO₂).

1 Mark Q3. Name the catalyst used in hydrogenation.

Answer: Nickel (Ni).

1 Mark Q4. Which type of hydrocarbons undergo addition reactions?

Answer: Unsaturated hydrocarbons.

1 Mark Q5. Name the product obtained by oxidation of ethanol.

Answer: Ethanoic acid.

2 Marks Q6. Write the combustion equation of methane.

Solution:
CH₄ + 2O₂ → CO₂ + 2H₂O + Heat

2 Marks Q7. Differentiate between saturated and unsaturated hydrocarbons.

Answer:
Saturated hydrocarbons contain only single C–C bonds, whereas unsaturated hydrocarbons contain double or triple bonds.

2 Marks Q8. What is an addition reaction? Give one example.

Answer:
An addition reaction is the addition of atoms/groups across a multiple bond.
CH₂=CH₂ + H₂ → CH₃–CH₃

2 Marks Q9. What is substitution reaction?

Answer:
A reaction in which one atom/group is replaced by another atom/group is called substitution reaction.
Example: CH₄ + Cl₂ → CH₃Cl + HCl.

2 Marks Q10. What is incomplete combustion?

Answer:
Combustion occurring due to insufficient oxygen is called incomplete combustion. It may produce CO and/or carbon.

3 Marks Q11. Explain combustion of carbon compounds with an example.

Solution:

• Carbon compounds react with oxygen.
• Heat and usually light are produced.
• Complete combustion generally forms CO₂ and H₂O.

Example: CH₄ + 2O₂ → CO₂ + 2H₂O + Heat

3 Marks Q12. Explain oxidation of ethanol.

Solution:
Ethanol is oxidised using an oxidising agent such as alkaline KMnO₄ or acidified K₂Cr₂O₇.

CH₃CH₂OH + 2[O] → CH₃COOH + H₂O

Thus ethanol changes into ethanoic acid.

3 Marks Q13. Explain hydrogenation of vegetable oils.

Answer:
Vegetable oils contain unsaturated compounds. Hydrogen is added to their multiple bonds in the presence of nickel catalyst. This increases saturation and is used in making vanaspati products.

3 Marks Q14. Explain substitution reaction of methane with chlorine.

Solution:
Methane reacts with chlorine in the presence of sunlight/UV light:

CH₄ + Cl₂ → CH₃Cl + HCl

One hydrogen atom of methane is replaced by chlorine.

3 Marks Q15. Why do unsaturated hydrocarbons undergo addition reactions?

Answer:
Unsaturated hydrocarbons contain double or triple bonds. The multiple bond can break partially and allow atoms/groups such as hydrogen to add across it.

4 Marks Q16. Explain complete and incomplete combustion.

Answer:
Complete combustion: Occurs when sufficient oxygen is available. It generally produces CO₂, H₂O and heat.

CH₄ + 2O₂ → CO₂ + 2H₂O

Incomplete combustion: Occurs when oxygen is insufficient. It can produce CO and/or carbon along with water.

4 Marks Q17. Compare addition and substitution reactions.

Addition	Substitution
Usually unsaturated compounds	Usually saturated compounds
Atoms/groups are added	One atom/group replaces another
Example: Ethene + H₂	Example: Methane + Cl₂

4 Marks Q18. Write the important chemical properties of carbon compounds.

Answer:

1. Combustion
2. Oxidation
3. Addition
4. Substitution

4 Marks Q19. Explain the role of nickel in hydrogenation.

Answer:
Nickel acts as a catalyst. It helps hydrogen molecules react with unsaturated compounds and increases the reaction rate. It is not consumed overall in the reaction.

4 Marks Q20. Write four important chemical reactions of carbon compounds.

Answer:

• Combustion
• Oxidation
• Addition
• Substitution

5 Marks Q21. Explain all major chemical properties of carbon compounds with suitable equations.

Solution:
1. Combustion: CH₄ + 2O₂ → CO₂ + 2H₂O + Heat

2. Oxidation: CH₃CH₂OH + 2[O] → CH₃COOH + H₂O

3. Addition: CH₂=CH₂ + H₂ → CH₃CH₃

4. Substitution: CH₄ + Cl₂ → CH₃Cl + HCl

5 Marks Q22. Explain hydrogenation and its industrial importance.

Answer:
Hydrogenation is addition of hydrogen to an unsaturated compound in the presence of a catalyst such as nickel.

CH₂=CH₂ + H₂ → CH₃CH₃

It is important in processing vegetable oils to obtain more saturated products such as vanaspati.

5 Marks Q23. Describe the chlorination of methane.

Solution:
In the presence of sunlight/UV light, chlorine reacts with methane.

CH₄ + Cl₂ → CH₃Cl + HCl

Further substitution can produce CH₂Cl₂, CHCl₃ and CCl₄. This is a substitution reaction.

5 Marks Q24. Explain why carbon compounds are commonly used as fuels.

Answer:
Many carbon compounds undergo combustion and release considerable amounts of heat. Hydrocarbons and alcohols are therefore used as fuels. Complete combustion generally produces CO₂ and H₂O along with heat.

5 Marks Q25. Explain the importance of oxidation reactions in carbon chemistry.

Answer:
Oxidation changes the structure and functional group of organic compounds. For example, ethanol can be oxidised to ethanoic acid. Oxidising agents such as KMnO₄ and K₂Cr₂O₇ are commonly used.

6 Marks Q26. Explain combustion, oxidation, addition and substitution reactions with equations.

Detailed Solution:

Combustion:
CH₄ + 2O₂ → CO₂ + 2H₂O + Heat

Oxidation:
CH₃CH₂OH + 2[O] → CH₃COOH + H₂O

Addition:
CH₂=CH₂ + H₂ → CH₃CH₃

Substitution:
CH₄ + Cl₂ → CH₃Cl + HCl

6 Marks Q27. Differentiate between complete and incomplete combustion and explain their products.

Solution:

Complete Combustion	Incomplete Combustion
Sufficient oxygen	Insufficient oxygen
CO₂ and H₂O mainly formed	CO and/or carbon may form
Usually cleaner flame	May produce smoky/sooty flame
More efficient energy release	Less efficient and may produce poisonous CO

6 Marks Q28. Explain addition reaction and hydrogenation of vegetable oils.

Solution:
Unsaturated compounds contain multiple bonds and undergo addition. Hydrogen can add across the multiple bond in the presence of nickel.

CH₂=CH₂ + H₂ → CH₃CH₃

Vegetable oils contain unsaturated compounds. Hydrogenation increases their saturation and is used in industrial processing of vegetable oils.

6 Marks Q29. Explain substitution reaction using methane as an example.

Solution:
Methane is a saturated hydrocarbon. In sunlight/UV light, chlorine replaces hydrogen atoms of methane step by step.

CH₄ + Cl₂ → CH₃Cl + HCl
CH₃Cl + Cl₂ → CH₂Cl₂ + HCl
CH₂Cl₂ + Cl₂ → CHCl₃ + HCl
CHCl₃ + Cl₂ → CCl₄ + HCl

This is called substitution because chlorine replaces hydrogen.

6 Marks Q30. Prepare a complete reaction map for the major chemical properties of carbon compounds.

CARBON COMPOUNDS

↓

🔥 COMBUSTION
→ CO₂ + H₂O + Heat

🧪 OXIDATION
Ethanol → Ethanoic Acid

➕ ADDITION
Ethene + H₂ → Ethane

🔄 SUBSTITUTION
Methane + Cl₂ → Chloromethane + HCl

14. Quick Revision – त्वरित पुनरावृत्ति

• Combustion: Carbon compound + O₂ → CO₂ + H₂O + Heat
• Incomplete combustion: May produce CO and/or carbon.
• Oxidation: Ethanol → Ethanoic acid
• Addition: Characteristic of unsaturated compounds.
• Hydrogenation: Unsaturated compound + H₂ → More saturated compound.
• Catalyst: Nickel (Ni) is commonly used for hydrogenation.
• Substitution: Characteristic of saturated hydrocarbons.
• Methane chlorination: CH₄ + Cl₂ → CH₃Cl + HCl

🔥 EXAM MEMORY TRICK

C – O – A – S

C = Combustion
O = Oxidation
A = Addition
S = Substitution

👉 Unsaturated → Addition
👉 Saturated → Substitution
👉 Ethanol → Oxidation → Ethanoic Acid
👉 Ethene + H₂ → Ethane
👉 Methane + Cl₂ → Chloromethane + HCl