Carbon and Its Compounds | Nomenclature of Carbon Compounds
Class 10 Science | Chapter 4 | CBSE + Foundation + Competitive Level
Nomenclature of Carbon Compounds | कार्बन यौगिकों का नामकरण
1. What is Nomenclature? | नामकरण क्या है?
English:
The systematic naming of organic compounds according to rules laid down by the International Union of Pure and Applied Chemistry (IUPAC) is called IUPAC nomenclature.
Hindi:
कार्बनिक यौगिकों को IUPAC द्वारा निर्धारित नियमों के अनुसार व्यवस्थित रूप से नाम देना नामकरण (Nomenclature) कहलाता है।
The systematic naming of organic compounds according to rules laid down by the International Union of Pure and Applied Chemistry (IUPAC) is called IUPAC nomenclature.
Hindi:
कार्बनिक यौगिकों को IUPAC द्वारा निर्धारित नियमों के अनुसार व्यवस्थित रूप से नाम देना नामकरण (Nomenclature) कहलाता है।
Example:
CH₄ → Methane
C₂H₆ → Ethane
C₃H₈ → Propane
C₄H₁₀ → Butane
CH₄ → Methane
C₂H₆ → Ethane
C₃H₈ → Propane
C₄H₁₀ → Butane
2. Why is Nomenclature Necessary? | नामकरण की आवश्यकता
Organic compounds are extremely numerous. A systematic naming system helps us:
- Identify a compound uniquely.
- Understand its carbon skeleton.
- Know the functional group.
- Determine the position of a functional group or multiple bond.
- Communicate chemical information internationally.
- यौगिक की पहचान आसानी से होती है।
- Carbon chain की जानकारी मिलती है।
- Functional group की पहचान होती है।
- Functional group या multiple bond की स्थिति ज्ञात होती है।
- पूरी दुनिया में एक समान नाम का उपयोग किया जा सकता है।
3. Carbon Chain Root Words | कार्बन श्रृंखला के मूल शब्द
| Number of Carbon Atoms | Root Word | Example |
|---|---|---|
| 1 | Meth- | Methane |
| 2 | Eth- | Ethane |
| 3 | Prop- | Propane |
| 4 | But- | Butane |
| 5 | Pent- | Pentane |
| 6 | Hex- | Hexane |
| 7 | Hept- | Heptane |
| 8 | Oct- | Octane |
| 9 | Non- | Nonane |
| 10 | Dec- | Decane |
Easy Trick:
1 Meth – 2 Eth – 3 Prop – 4 But – 5 Pent – 6 Hex – 7 Hept – 8 Oct – 9 Non – 10 Dec
1 Meth – 2 Eth – 3 Prop – 4 But – 5 Pent – 6 Hex – 7 Hept – 8 Oct – 9 Non – 10 Dec
4. Suffixes in Carbon Compounds | प्रत्यय
| Type of Compound | Bond / Functional Group | Suffix | Example |
|---|---|---|---|
| Alkane | C–C | -ane | Ethane |
| Alkene | C=C | -ene | Ethene |
| Alkyne | C≡C | -yne | Ethyne |
| Alcohol | –OH | -ol | Ethanol |
| Aldehyde | –CHO | -al | Ethanal |
| Ketone | >C=O | -one | Propanone |
| Carboxylic Acid | –COOH | -oic acid | Ethanoic acid |
5. Naming of Alkanes | एल्केन का नामकरण
Alkanes contain only single bonds.
General formula:
CₙH₂ₙ₊₂
Examples:
| Formula | Name |
|---|---|
| CH₄ | Methane |
| C₂H₆ | Ethane |
| C₃H₈ | Propane |
| C₄H₁₀ | Butane |
| C₅H₁₂ | Pentane |
| C₆H₁₄ | Hexane |
6. Naming of Alkenes | एल्कीन का नामकरण
Alkenes contain at least one carbon-carbon double bond.
The suffix -ene is used.
| Formula | Name |
|---|---|
| C₂H₄ | Ethene |
| C₃H₆ | Propene |
| C₄H₈ | Butene |
| C₅H₁₀ | Pentene |
7. Naming of Alkynes | एल्काइन का नामकरण
Alkynes contain at least one carbon-carbon triple bond.
The suffix -yne is used.
| Formula | Name |
|---|---|
| C₂H₂ | Ethyne |
| C₃H₄ | Propyne |
| C₄H₆ | Butyne |
| C₅H₈ | Pentyne |
8. Functional Groups and Their Names | क्रियात्मक समूह
| Functional Group | Name | Suffix | Example |
|---|---|---|---|
| –OH | Alcohol | -ol | Ethanol |
| –CHO | Aldehyde | -al | Ethanal |
| >C=O | Ketone | -one | Propanone |
| –COOH | Carboxylic acid | -oic acid | Ethanoic acid |
9. Basic Steps of IUPAC Nomenclature | नामकरण के मुख्य चरण
Step 1: Find the longest continuous carbon chain.
Step 2: Identify the principal functional group or multiple bond.
Step 3: Number the carbon chain from the appropriate end.
Step 4: Identify substituents such as methyl or ethyl.
Step 5: Assign locants (position numbers).
Step 6: Write the name using the correct prefix, root and suffix.
Step 2: Identify the principal functional group or multiple bond.
Step 3: Number the carbon chain from the appropriate end.
Step 4: Identify substituents such as methyl or ethyl.
Step 5: Assign locants (position numbers).
Step 6: Write the name using the correct prefix, root and suffix.
10. Longest Carbon Chain Rule | सबसे लंबी श्रृंखला
The parent chain is generally the longest continuous carbon chain containing the principal functional group and, where applicable, the maximum number of multiple bonds.
Example:
CH₃–CH₂–CH₂–CH₃
There are four carbon atoms. Therefore: But + ane = Butane
Example:
CH₃–CH₂–CH₂–CH₃
There are four carbon atoms. Therefore: But + ane = Butane
11. Numbering of Carbon Chain | कार्बन श्रृंखला की संख्या
The carbon chain is numbered from the end that gives the important feature the lowest possible locant.
For a simple functional-group example:
CH₃–CH₂–CH₂–OH
Numbering starts from the –OH end:
CH₃–CH₂–CH₂–OH
Numbering starts from the –OH end:
HO–CH₂–CH₂–CH₃
Propan-1-ol
Propan-1-ol
Important: Numbering is not always simply from the nearest substituent. The principal functional group and multiple bonds receive appropriate priority under the nomenclature rules.
12. Prefixes for Alkyl Groups | एल्किल समूह
| Alkyl Group | Formula | Name |
|---|---|---|
| –CH₃ | CH₃– | Methyl |
| –C₂H₅ | C₂H₅– | Ethyl |
| –C₃H₇ | C₃H₇– | Propyl |
| –C₄H₉ | C₄H₉– | Butyl |
13. Naming Branched-Chain Compounds | शाखित श्रृंखला का नामकरण
Consider:
CH₃–CH(CH₃)–CH₃
The longest chain contains three carbon atoms: Propane There is a methyl group attached to carbon number 2. Therefore the name is:
CH₃–CH(CH₃)–CH₃
The longest chain contains three carbon atoms: Propane There is a methyl group attached to carbon number 2. Therefore the name is:
2-Methylpropane
Consider:
CH₃–CH(CH₃)–CH₂–CH₃
Longest chain = 4 carbons → Butane
Methyl group = carbon 2
Name:
CH₃–CH(CH₃)–CH₂–CH₃
Longest chain = 4 carbons → Butane
Methyl group = carbon 2
Name:
2-Methylbutane
14. More Than One Substituent | एक से अधिक प्रतिस्थापी
If identical substituents occur more than once, prefixes are used:
Here two methyl groups are present.
- 2 → di
- 3 → tri
- 4 → tetra
Here two methyl groups are present.
15. Position of Double Bond | द्विबंध की स्थिति
For alkenes, the position of the double bond is indicated by a number.
Example:
CH₂=CH–CH₂–CH₃
There are four carbon atoms → but-
Double bond starts at carbon 1.
Name:
There are four carbon atoms → but-
Double bond starts at carbon 1.
Name:
But-1-ene
Another example:
CH₃–CH=CH–CH₃
Double bond begins at carbon 2.
Name:
Double bond begins at carbon 2.
Name:
But-2-ene
16. Position of Triple Bond | त्रिबंध की स्थिति
Example:
CH≡C–CH₂–CH₃
Four carbon atoms → but-
Triple bond begins at carbon 1.
Name:
Four carbon atoms → but-
Triple bond begins at carbon 1.
Name:
But-1-yne
17. Naming Alcohols | अल्कोहॉल का नामकरण
Alcohols contain the functional group:
–OH
The suffix -ol is used.
Example: CH₃–CH₂–OH
2 carbon atoms → eth-
Alcohol → -ol
Name: Ethanol
Example: CH₃–CH₂–OH
2 carbon atoms → eth-
Alcohol → -ol
Name: Ethanol
Example:
CH₃–CH₂–CH₂–OH
Three carbon atoms → prop-
–OH at carbon 1.
Name: Propan-1-ol
Three carbon atoms → prop-
–OH at carbon 1.
Name: Propan-1-ol
18. Naming Aldehydes | एल्डिहाइड का नामकरण
Aldehyde functional group:
–CHO
Suffix:
-al
Example: CH₃–CHO
Two carbon atoms → eth-
Aldehyde → -al
Name = Ethanal
Example: CH₃–CHO
Two carbon atoms → eth-
Aldehyde → -al
Name = Ethanal
19. Naming Ketones | कीटोन का नामकरण
Ketone functional group:
>C=O
Suffix:
-one
Example: CH₃–CO–CH₃
Three carbon atoms → prop-
Ketone → -one
Name = Propanone
Example: CH₃–CO–CH₃
Three carbon atoms → prop-
Ketone → -one
Name = Propanone
20. Naming Carboxylic Acids | कार्बोक्सिलिक अम्ल
Carboxylic acid functional group:
–COOH
Suffix:
-oic acid
Example: CH₃–COOH
Two carbon atoms → eth-
Acid → -oic acid
Name = Ethanoic acid
Example: CH₃–COOH
Two carbon atoms → eth-
Acid → -oic acid
Name = Ethanoic acid
21. General Naming Pattern | सामान्य नामकरण प्रारूप
Prefix + Parent/Root + Suffix
For example:
2-Methylpropane
2 → position
Methyl → substituent
Prop → 3 carbon parent chain
ane → single bonds
For example:
2-Methylpropane
2 → position
Methyl → substituent
Prop → 3 carbon parent chain
ane → single bonds
22. Important IUPAC Examples
| Structure / Formula | IUPAC Name |
|---|---|
| CH₄ | Methane |
| CH₃–CH₃ | Ethane |
| CH₃–CH₂–CH₃ | Propane |
| CH₃–CH₂–CH₂–CH₃ | Butane |
| CH₂=CH₂ | Ethene |
| CH₂=CH–CH₃ | Propene |
| CH≡CH | Ethyne |
| CH₃–CH₂–OH | Ethanol |
| CH₃–CHO | Ethanal |
| CH₃–CO–CH₃ | Propanone |
| CH₃–COOH | Ethanoic acid |
| CH₃–CH(CH₃)–CH₃ | 2-Methylpropane |
23. 30 MCQs | बहुविकल्पीय प्रश्न
Q1. The systematic naming of organic compounds is called:
A. Isomerism
B. Nomenclature
C. Catenation
D. Polymerisation
Answer: B
Q2. Which organisation is associated with systematic chemical nomenclature?
A. WHO
B. UNESCO
C. IUPAC
D. UNICEF
Answer: C
Q3. The root word for one carbon atom is:
A. Meth
B. Eth
C. Prop
D. But
Answer: A
Q4. The root word for four carbon atoms is:
A. Prop
B. Pent
C. But
D. Hex
Answer: C
Q5. The suffix used for alkanes is:
A. -ene
B. -yne
C. -ol
D. -ane
Answer: D
Q6. The suffix -ene indicates:
A. Double bond
B. Triple bond
C. Alcohol
D. Carboxylic acid
Answer: A
Q7. The suffix -yne indicates:
A. Single bond
B. Double bond
C. Triple bond
D. –OH group
Answer: C
Q8. What is the IUPAC name of CH₄?
A. Ethane
B. Methane
C. Propane
D. Butane
Answer: B
Q9. What is the IUPAC name of C₂H₆?
A. Methane
B. Propane
C. Ethane
D. Ethene
Answer: C
Q10. The IUPAC name of CH₂=CH₂ is:
A. Ethane
B. Ethyne
C. Ethanol
D. Ethene
Answer: D
Q11. The IUPAC name of CH≡CH is:
A. Ethyne
B. Ethene
C. Ethane
D. Methyne
Answer: A
Q12. The functional group of alcohol is:
A. –COOH
B. –CHO
C. –OH
D. –CO–
Answer: C
Q13. CH₃CH₂OH is:
A. Methanol
B. Ethanol
C. Propanol
D. Ethanal
Answer: B
Q14. The suffix used for alcohols is:
A. -ol
B. -al
C. -one
D. -oic acid
Answer: A
Q15. CH₃CHO is named:
A. Ethanol
B. Ethanoic acid
C. Ethanal
D. Ethanone
Answer: C
Q16. The suffix for aldehydes is:
A. -one
B. -ol
C. -al
D. -yne
Answer: C
Q17. CH₃COCH₃ is:
A. Propanone
B. Propanol
C. Propanal
D. Propanoic acid
Answer: A
Q18. The functional group of carboxylic acids is:
A. –OH
B. –CHO
C. –COOH
D. –O–
Answer: C
Q19. The IUPAC name of CH₃COOH is:
A. Methanoic acid
B. Ethanoic acid
C. Propanoic acid
D. Ethanol
Answer: B
Q20. The alkyl group –CH₃ is called:
A. Ethyl
B. Propyl
C. Methyl
D. Butyl
Answer: C
Q21. The alkyl group –C₂H₅ is called:
A. Methyl
B. Ethyl
C. Propyl
D. Butyl
Answer: B
Q22. What is the IUPAC name of CH₃CH(CH₃)CH₃?
A. Butane
B. 1-Methylpropane
C. 2-Methylpropane
D. Pentane
Answer: C
Q23. In 2-methylpropane, the parent chain contains:
A. 2 carbon atoms
B. 3 carbon atoms
C. 4 carbon atoms
D. 5 carbon atoms
Answer: B
Q24. What does the prefix "di-" indicate?
A. One substituent
B. Two identical substituents
C. Three substituents
D. Four substituents
Answer: B
Q25. What is the IUPAC name of CH₂=CHCH₂CH₃?
A. Butane
B. But-2-ene
C. But-1-ene
D. Propene
Answer: C
Q26. What is the IUPAC name of CH₃CH=CHCH₃?
A. But-1-ene
B. But-2-ene
C. Butane
D. Butyne
Answer: B
Q27. Which is the correct IUPAC name of CH₃CH₂CH₂OH?
A. Propanol
B. Propan-1-ol
C. Propan-2-ol
D. Ethanol
Answer: B
Q28. Which rule is important when selecting a parent chain?
A. Select the shortest chain only
B. Select any random chain
C. Select an appropriate longest continuous chain
D. Select only a branched chain
Answer: C
Q29. What is the IUPAC name of CH₃CH₂CH₃?
A. Methane
B. Ethane
C. Propane
D. Butane
Answer: C
Q30. In "2-methylbutane", the number 2 represents:
A. Number of carbon atoms
B. Position of methyl group
C. Number of hydrogen atoms
D. Molecular mass
Answer: B
24. 30 Subjective Questions | वर्णनात्मक प्रश्न
1 Mark
Q1. What is nomenclature?
नामकरण क्या है?
Q1. What is nomenclature?
नामकरण क्या है?
Answer: The systematic naming of chemical compounds according to prescribed rules is called nomenclature.
1 Mark
Q2. What does IUPAC stand for?
Q2. What does IUPAC stand for?
Answer: International Union of Pure and Applied Chemistry.
1 Mark
Q3. Write the root word for three carbon atoms.
Q3. Write the root word for three carbon atoms.
Answer: Prop-
1 Mark
Q4. Write the suffix used for alkenes.
Q4. Write the suffix used for alkenes.
Answer: -ene
1 Mark
Q5. Name the functional group –OH.
Q5. Name the functional group –OH.
Answer: Hydroxyl group / Alcohol functional group.
2 Marks
Q6. Write the IUPAC names of CH₄ and C₂H₆.
Q6. Write the IUPAC names of CH₄ and C₂H₆.
Answer: CH₄ = Methane; C₂H₆ = Ethane.
2 Marks
Q7. Write the IUPAC names of C₂H₄ and C₂H₂.
Q7. Write the IUPAC names of C₂H₄ and C₂H₂.
Answer: C₂H₄ = Ethene; C₂H₂ = Ethyne.
2 Marks
Q8. Write two rules of IUPAC nomenclature.
Q8. Write two rules of IUPAC nomenclature.
Answer:
- Select an appropriate longest parent carbon chain.
- Number the chain according to the lowest appropriate locant rule.
2 Marks
Q9. Name the following compounds:
(a) CH₃CH₂OH
(b) CH₃COOH
Q9. Name the following compounds:
(a) CH₃CH₂OH
(b) CH₃COOH
Answer:
(a) Ethanol
(b) Ethanoic acid
(a) Ethanol
(b) Ethanoic acid
2 Marks
Q10. What are methyl and ethyl groups?
Q10. What are methyl and ethyl groups?
Answer:
Methyl = –CH₃
Ethyl = –C₂H₅
Methyl = –CH₃
Ethyl = –C₂H₅
3 Marks
Q11. Explain the importance of the longest carbon chain in nomenclature.
Q11. Explain the importance of the longest carbon chain in nomenclature.
Solution:
The longest appropriate continuous carbon chain is selected as the parent chain. Its carbon count determines the root name such as meth-, eth-, prop-, but-, etc. Substituents and functional groups are then identified in relation to this parent chain.
The longest appropriate continuous carbon chain is selected as the parent chain. Its carbon count determines the root name such as meth-, eth-, prop-, but-, etc. Substituents and functional groups are then identified in relation to this parent chain.
3 Marks
Q12. Name the following compounds:
(a) CH₃CH₂CH₃
(b) CH₃CH₂CH₂CH₃
(c) CH₃CH₂CH₂CH₂CH₃
Q12. Name the following compounds:
(a) CH₃CH₂CH₃
(b) CH₃CH₂CH₂CH₃
(c) CH₃CH₂CH₂CH₂CH₃
Answer:
(a) Propane
(b) Butane
(c) Pentane
(a) Propane
(b) Butane
(c) Pentane
3 Marks
Q13. Explain the meaning of root word and suffix in nomenclature.
Q13. Explain the meaning of root word and suffix in nomenclature.
Answer:
Root word: Indicates the number of carbon atoms in the parent chain.
Suffix: Indicates the type of bonding or principal functional group.
Root word: Indicates the number of carbon atoms in the parent chain.
Suffix: Indicates the type of bonding or principal functional group.
3 Marks
Q14. Name the following:
(a) CH₂=CH₂
(b) CH₂=CHCH₃
(c) CH≡CH
Q14. Name the following:
(a) CH₂=CH₂
(b) CH₂=CHCH₃
(c) CH≡CH
Answer:
(a) Ethene
(b) Propene
(c) Ethyne
(a) Ethene
(b) Propene
(c) Ethyne
3 Marks
Q15. What is a substituent? Give two examples.
Q15. What is a substituent? Give two examples.
Answer:
A group attached to the parent carbon chain in place of a hydrogen atom is called a substituent. Examples:
–CH₃ = methyl
–C₂H₅ = ethyl
A group attached to the parent carbon chain in place of a hydrogen atom is called a substituent. Examples:
–CH₃ = methyl
–C₂H₅ = ethyl
4 Marks
Q16. Explain the basic steps involved in IUPAC nomenclature.
Q16. Explain the basic steps involved in IUPAC nomenclature.
Solution:
- Select the appropriate parent carbon chain.
- Identify the principal functional group or multiple bond.
- Number the parent chain appropriately.
- Identify substituents and their positions.
- Use the correct root and suffix.
- Combine all parts to obtain the systematic name.
4 Marks
Q17. Explain the nomenclature of 2-methylpropane.
Q17. Explain the nomenclature of 2-methylpropane.
Solution:
Structure:
CH₃–CH(CH₃)–CH₃
Longest continuous chain = 3 carbon atoms → Propane.
Substituent = methyl.
Methyl group is attached to carbon 2.
Name = 2-Methylpropane.
CH₃–CH(CH₃)–CH₃
Longest continuous chain = 3 carbon atoms → Propane.
Substituent = methyl.
Methyl group is attached to carbon 2.
Name = 2-Methylpropane.
4 Marks
Q18. Explain the difference between -ane, -ene and -yne.
Q18. Explain the difference between -ane, -ene and -yne.
| Suffix | Bond | Example |
|---|---|---|
| -ane | Single | Ethane |
| -ene | Double | Ethene |
| -yne | Triple | Ethyne |
4 Marks
Q19. Give the IUPAC names of:
(a) CH₃CH₂OH
(b) CH₃CHO
(c) CH₃COCH₃
(d) CH₃COOH
Q19. Give the IUPAC names of:
(a) CH₃CH₂OH
(b) CH₃CHO
(c) CH₃COCH₃
(d) CH₃COOH
Answer:
(a) Ethanol
(b) Ethanal
(c) Propanone
(d) Ethanoic acid
(a) Ethanol
(b) Ethanal
(c) Propanone
(d) Ethanoic acid
4 Marks
Q20. Explain the naming of alkenes with suitable examples.
Q20. Explain the naming of alkenes with suitable examples.
Solution:
Alkenes contain at least one C=C double bond. The parent chain is selected and the suffix -ene is used. The position of the double bond may be indicated by a locant. Examples:
CH₂=CH₂ → Ethene
CH₂=CHCH₂CH₃ → But-1-ene
CH₃CH=CHCH₃ → But-2-ene
Alkenes contain at least one C=C double bond. The parent chain is selected and the suffix -ene is used. The position of the double bond may be indicated by a locant. Examples:
CH₂=CH₂ → Ethene
CH₂=CHCH₂CH₃ → But-1-ene
CH₃CH=CHCH₃ → But-2-ene
5 Marks
Q21. Explain the IUPAC naming system for carbon compounds.
Q21. Explain the IUPAC naming system for carbon compounds.
Solution:
IUPAC nomenclature gives systematic names to organic compounds. The main steps are:
IUPAC nomenclature gives systematic names to organic compounds. The main steps are:
- Select an appropriate parent carbon chain.
- Count carbon atoms and select the correct root word.
- Identify the functional group or multiple bond.
- Number the chain appropriately.
- Identify substituents and their positions.
- Use the appropriate suffix.
5 Marks
Q22. Explain root words from 1 to 10 carbon atoms.
Q22. Explain root words from 1 to 10 carbon atoms.
| Carbon | Root |
|---|---|
| 1 | Meth |
| 2 | Eth |
| 3 | Prop |
| 4 | But |
| 5 | Pent |
| 6 | Hex |
| 7 | Hept |
| 8 | Oct |
| 9 | Non |
| 10 | Dec |
5 Marks
Q23. Explain the naming of alcohols, aldehydes, ketones and carboxylic acids.
Q23. Explain the naming of alcohols, aldehydes, ketones and carboxylic acids.
| Compound | Functional Group | Suffix | Example |
|---|---|---|---|
| Alcohol | –OH | -ol | Ethanol |
| Aldehyde | –CHO | -al | Ethanal |
| Ketone | >C=O | -one | Propanone |
| Carboxylic acid | –COOH | -oic acid | Ethanoic acid |
5 Marks
Q24. Explain the nomenclature of branched-chain compounds with an example.
Q24. Explain the nomenclature of branched-chain compounds with an example.
Solution:
Example:
CH₃–CH(CH₃)–CH₂–CH₃
Longest chain = 4 carbon atoms → Butane.
Substituent = methyl.
Methyl group is located at carbon 2.
IUPAC name = 2-Methylbutane.
CH₃–CH(CH₃)–CH₂–CH₃
Longest chain = 4 carbon atoms → Butane.
Substituent = methyl.
Methyl group is located at carbon 2.
IUPAC name = 2-Methylbutane.
5 Marks
Q25. Explain the role of locants in IUPAC nomenclature.
Q25. Explain the role of locants in IUPAC nomenclature.
Answer:
Locants are numbers used to indicate the position of substituents, functional groups or multiple bonds in a carbon chain. Examples:
But-1-ene → double bond at carbon 1.
But-2-ene → double bond at carbon 2.
2-Methylpropane → methyl group at carbon 2.
Locants are numbers used to indicate the position of substituents, functional groups or multiple bonds in a carbon chain. Examples:
But-1-ene → double bond at carbon 1.
But-2-ene → double bond at carbon 2.
2-Methylpropane → methyl group at carbon 2.
6 Marks
Q26. Explain the complete procedure for naming a branched carbon compound.
Q26. Explain the complete procedure for naming a branched carbon compound.
Solution:
The procedure is:
Longest chain = Butane
Substituent = Methyl
Position = 2
Name = 2-Methylbutane.
- Identify the longest appropriate parent chain.
- Count the number of carbon atoms.
- Choose the corresponding root word.
- Number the chain from the appropriate end.
- Identify every substituent.
- Determine the position of each substituent.
- Use di-, tri-, etc. if identical substituents occur more than once.
- Combine the locants, substituent names, parent name and suffix.
Longest chain = Butane
Substituent = Methyl
Position = 2
Name = 2-Methylbutane.
6 Marks
Q27. Give the IUPAC names of the following compounds:
(a) CH₃CH₂CH₂CH₃
(b) CH₃CH(CH₃)CH₃
(c) CH₂=CHCH₃
(d) CH₃CH=CHCH₃
(e) CH₃CH₂OH
(f) CH₃COOH
Q27. Give the IUPAC names of the following compounds:
(a) CH₃CH₂CH₂CH₃
(b) CH₃CH(CH₃)CH₃
(c) CH₂=CHCH₃
(d) CH₃CH=CHCH₃
(e) CH₃CH₂OH
(f) CH₃COOH
Answer:
(a) Butane
(b) 2-Methylpropane
(c) Propene
(d) But-2-ene
(e) Ethanol
(f) Ethanoic acid
(a) Butane
(b) 2-Methylpropane
(c) Propene
(d) But-2-ene
(e) Ethanol
(f) Ethanoic acid
6 Marks
Q28. Explain how the number of carbon atoms and type of bonding determine the name of a hydrocarbon.
Q28. Explain how the number of carbon atoms and type of bonding determine the name of a hydrocarbon.
Solution:
The number of carbon atoms determines the root word:
1 → meth, 2 → eth, 3 → prop, 4 → but, etc.
The type of carbon-carbon bonding determines the suffix:
Single bond → -ane
Double bond → -ene
Triple bond → -yne
Examples: CH₃CH₃ → Ethane
CH₂=CH₂ → Ethene
CH≡CH → Ethyne
The number of carbon atoms determines the root word:
1 → meth, 2 → eth, 3 → prop, 4 → but, etc.
The type of carbon-carbon bonding determines the suffix:
Single bond → -ane
Double bond → -ene
Triple bond → -yne
Examples: CH₃CH₃ → Ethane
CH₂=CH₂ → Ethene
CH≡CH → Ethyne
6 Marks
Q29. A compound has the structure CH₃–CH(CH₃)–CH₂–CH₃. Determine its IUPAC name and explain each part of the name.
Q29. A compound has the structure CH₃–CH(CH₃)–CH₂–CH₃. Determine its IUPAC name and explain each part of the name.
Solution:
Longest continuous chain contains 4 carbon atoms.
Therefore root = But-
There is one methyl substituent.
Numbering from the nearer end gives methyl at carbon 2.
Single bonds → -ane
Therefore: 2-Methylbutane
2 = position of methyl group
Methyl = substituent
But = four-carbon parent chain
ane = single bonds
Therefore root = But-
There is one methyl substituent.
Numbering from the nearer end gives methyl at carbon 2.
Single bonds → -ane
Therefore: 2-Methylbutane
2 = position of methyl group
Methyl = substituent
But = four-carbon parent chain
ane = single bonds
6 Marks
Q30. Explain why IUPAC nomenclature is important in the study of carbon compounds.
Q30. Explain why IUPAC nomenclature is important in the study of carbon compounds.
Answer:
IUPAC nomenclature is important because:
- It gives each compound a systematic name.
- It avoids confusion caused by different common names.
- It helps identify the carbon skeleton.
- It indicates important functional groups and bonding features.
- It helps communicate chemical information internationally.
- It provides a systematic method for naming a very large number of organic compounds.
25. Quick Revision | त्वरित पुनरावृत्ति
⭐ IUPAC Naming Formula:
Position + Prefix + Root + Suffix
Root Words:
1 Meth | 2 Eth | 3 Prop | 4 But | 5 Pent | 6 Hex | 7 Hept | 8 Oct | 9 Non | 10 Dec
Important Suffixes:
Alkane → -ane
Alkene → -ene
Alkyne → -yne
Alcohol → -ol
Aldehyde → -al
Ketone → -one
Carboxylic acid → -oic acid
Position + Prefix + Root + Suffix
Root Words:
1 Meth | 2 Eth | 3 Prop | 4 But | 5 Pent | 6 Hex | 7 Hept | 8 Oct | 9 Non | 10 Dec
Important Suffixes:
Alkane → -ane
Alkene → -ene
Alkyne → -yne
Alcohol → -ol
Aldehyde → -al
Ketone → -one
Carboxylic acid → -oic acid
26. Exam Booster | परीक्षा के लिए महत्वपूर्ण
Remember these examples:
CH₄ → Methane
C₂H₆ → Ethane
C₃H₈ → Propane
C₄H₁₀ → Butane
CH₂=CH₂ → Ethene
CH₂=CHCH₃ → Propene
CH≡CH → Ethyne
CH₃CH₂OH → Ethanol
CH₃CHO → Ethanal
CH₃COCH₃ → Propanone
CH₃COOH → Ethanoic acid
CH₃CH(CH₃)CH₃ → 2-Methylpropane
CH₄ → Methane
C₂H₆ → Ethane
C₃H₈ → Propane
C₄H₁₀ → Butane
CH₂=CH₂ → Ethene
CH₂=CHCH₃ → Propene
CH≡CH → Ethyne
CH₃CH₂OH → Ethanol
CH₃CHO → Ethanal
CH₃COCH₃ → Propanone
CH₃COOH → Ethanoic acid
CH₃CH(CH₃)CH₃ → 2-Methylpropane
27. One-Line Revision | एक लाइन में पूरा Chapter
Number of Carbon → Root Word → Bond/Functional Group → Suffix → Position/Prefix → IUPAC Name
कार्बन की संख्या → Root Word → Bond/Functional Group → Suffix → Position/Prefix → नाम
कार्बन की संख्या → Root Word → Bond/Functional Group → Suffix → Position/Prefix → नाम
