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CBSE NOTES ⇒ Class 10th ⇒ Science ⇒ 4. Carbon and its Compounds

4. Carbon and its Compounds

Functional Group and Nomenclature of Hydrocarbons


Chapter 4. Carbon And Its Compounds


Functional Group: 

Functional group is a group of an atom or atoms in any carbonic compound which are bonded each other in special manner. That is generally region of chemical reactivity in carbonic atoms.

Oxygen, chlorine, sulpher, nitrogen and other elements can be presence as a part of a functional group in carbonic compounds. 

Hetroatoms: The element which replaces hydrogen in a compound is called hetroatom. 

Example: Oxygen, chlorine, sulpher, nitrogen and other elements can be presence as a part of a functional group in carbonic compounds, such elements are called hetroatoms.

Some List of Functional Groups: 

(i) Halogen: Halogens are non-metal elements like fluorine, chlorine, bromine and Iodine etc situated in modern periodic table in group 17. 

Functional Group formula of functional group  Hetroatom
Halogen

-Cl (Sufix is used Chloro) 

-Br (Sufix is used Bromo) 

-I (Sufix is used Iodo) 

 Cl (Chlorine) 

 Br (Bromine) 

 I (Iodine) 

(ii) Alcohol: Alcohol is another function group which joining to a series of hydrocarbon forms the group of atoms 

Example: - OH

(-OH) joins to hydrocarbon like alkane form various type of alcohols, such methanol, ethanol and propanol etc.  

(iii) Aldehyde: It is a functional group in which carbon atom linked with a single oxygen atom in double bond along with one hydrogen atom. 

        

(iv) Ketone: Ketone is also a functional group which joins to hydrocarbons form a series of molecules. In ketone carbon atom linked with a single oxygen atom in double bond. 

          

(v) Carboxylic acid: It is also a functional group, in which a carbon atom is  linked with oxygen atom in double bond and also linked with hydroxide.

          

Homologous Series: 

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

Examples: 

Carbon chain with alkane Homologous Series with halogen (-Cl) Homologous Series with halogen (-Br) Homologous Series with halogen (-I) Homologous Series with Alcohol (-OH) Homologous Series with Aldehyde (-CHO)    
 CH4  CH3-Cl CH3-Br  CH3-I  CH3-OH H-CHO    
 C2H6  C2H5-Cl  C2H5-Br  C2H5-I  C2H5-OH CH3-CHO    
 C3H8  C3H7-Cl  C3H7-Br  C3H7-I  C3H7-OH C2H5-CHO    
 C4H10  C4H9-Cl  C4H9-Br  C4H9-I  C4H9-OH C3H7-CHO    
 C5H12  C5H11-Cl  C5H11-Br  C5H11-I  C5H11-OH C4H9-CHO    
 C6H14  C6H13-Cl  C6H13-Br  C6H13-I  C6H13-OH C5H11-CHO    

Increasing in molecular Mass in Homologous series: 

As the molecular mass increases in any homologous series, a gradation in physical properties is seen. This is because the melting points and boiling points increase with increasing molecular mass. Other physical properties such as solubility in a particular solvent also show a similar gradation. But the chemical properties, which are determined solely by the functional group, remain similar in a homologous series.

Nomenclature of carbon Compounds: 

Naming of organic compound systematically called as nomenclature. 

IUPAC Name: 

Name formed by this nomenclature is called IUPAC name of molecules.

Nomenclature of Hydrocarbons:

According to presence of carbon atoms in hydrocarbon molecules naming of molecules are as follows: 

 No. of carbon atoms Name   Example With Alkane (H.C)
 1 carbon atom  Meth-  Methane
 2 carbon atoms   Eth-  Ethane 
 3 carbon atoms  Prop-  Propane
 4 carbon atoms  But-  Butane
 5 carbon atoms  Pent-  Pentane 
 6carbon atoms  Hex-  Hexane
 7 carbon atoms  Hept-  Heptane
 8 carbon atoms  Oct-  Octane
 9 carbon atoms  Non-  Nonane
 10 carbon atoms  Dec-  Decane 

We have already known that Hydrocarbons are three types and their nomenclature are as follows:

(i) Alkane (Single bond):

Functional Group Halogen and its nomenclature:

For -(Cl) "chloro" is used, (-Br) "Bromo" is used and (-I) "Iodo" is used. 

(A) Alkane with Chlorine

Molecular formula of F.G halogen (chlorine) IUPAC Name  
 CH3-Cl Chloro-methane  
C2H5-Cl Chloro-ethane  
C3H7-Cl Chloro-propane  
 C4H9-Cl Chloro-butane  
C5H11-Cl Chloro-pentane  
C6H13-Cl Chloro-hexane  

(B) Alkane with Bromine

Molecular formula of F.G halogen (Bromine) IUPAC Name  
 CH3-Br Bromo-methane  
C2H5-Br Bromo-ethane  
C3H7-Br Bromo-propane  
 C4H9-Br Bromo-butane  
C5H11-Br Bromo-pentane  
C6H13-Br Bromo-hexane

(C) Alkane with Iodine

Molecular formula of F.G halogen (Bromine) IUPAC Name  
 CH3-I Iodo-methane  
C2H5-I Iodo-ethane  
C3H7-I Iodo-propane  
 C4H9-I Iodo-butane  
C5H11-I Iodo-pentane  
C6H13-I Iodo-hexane

Functional Group Alcohol and its nomenclature:

 To give the name to Alcohol group we use a "suffix" -"ol" With the name of simple Alkane

(D)Alcohol

Molecular formula of F.G Alcohol (-OH)  IUPAC Name  
 CH3-OH Methanol  
C2H5-OH Ethanol  
C3H7-OH Propanol  
 C4H9-OH Butanol  
C5H11-OH Pentanol  
C6H13-OH Hexanol

Note: Above Examples (A), (B), (C) and (D) are also Homologous series

(ii) Alkene (Double bond)

(iii) Alkyne (Triple bond) 

 

Other Pages of this Chapter:

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Study Materials List:

CBSE NOTES ⇒ Class 10th ⇒ Science
1. Chemical Reactions and Equations
2. Acids, Bases and Salts
3. Metals and Non-metals
4. Carbon and its Compounds
5. Periodic Classification of Elements
6. Life Processes
7. Control and Coordination
8. How do Organisms Reproduce
9. Heredity and Evolution
10. Light-Reflection and Refraction
11. Human Eye and Colourful World
12. Electricity
13. Magnetic Effects of Electric Current
14. Sources of Energy
15. Our Environment
16. Management of Natural Resources

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