Carbon and its Compounds Quick Revision Class 10 Science RBSE

Carbon and its compounds quick revision Class 10 Science is an important topic for students preparing for board exam. This chapter explains the versatile nature of carbon, covalent bonding, allotropes, homologous series, functional groups and important organic compounds like ethanol, ethanoic acid.

This quick revision notes based on the NCERT Science Class 10 syllabus followed by RBSE help students revise key concepts, reactions and definition in a short time. This is useful for last minute preparation.

After reading these notes, you can solve questions of the chapter and practice with MCQs for better understanding.

Importance of Carbon

• Carbon is present in all living organisms and forms the basis of life.
• It is found in earth’s crust as carbonates, coal and petroleum.
• It is found in atmosphere as carbon dioxide.
• Food, clothes, medicines, fuels, plastics and paper are made of carbon compounds.
• Carbon forms million of compounds due to its unique properties.

 

Bonding in Carbon

Atomic number – 6

Valency – 4 (tetravalent)

Electronic configuration – 1s² 2s² 2p²

Carbon shares electrons to form covalent bonds with carbon atoms and other atoms.

Properties of Covalent Compounds

i.These compounds have low melting and boiling points

ii.They are found in gaseous and liquid states mostly.

iii.They are poor conductors of electricity.

Exception: Graphite (allotrope of carbon) is conductor of electricity.

Examples: CH₄, CH₃CH₂OH, CHCl₃ etc.

Carbon exists in different structural forms.

(i)    Diamond

·     Each carbon bonded to 4 carbon atoms.

·     It has rigid 3D structure.

·     It is the hardest natural substance.

·     It has high melting point.

·     It is nonconductor of electricity.

  (ii)    Graphite

            Each carbon bonded to 3 carbon atoms.

            It has hexagonal layered structure

             It has free electrons so conducts electricity.

           It is soft and slippery due to layered slide.

   (iii)   Fullerene

           Buckminsterfullerene is C-60 a well-known allotrope of carbon.

                               It contains 60 carbon atoms.

           It has football-like structure so it is called bucky ball.

 

 

Versatile Nature of Carbon

Carbon makes large number of compounds due to following properties:

Catenation

The ability to form a long chain, branches and rings with other carbon atoms.

C – C bonds are strong and stable.

Tetravalency

Each carbon atoms can bonds with four atoms.

Saturated and Unsaturated Hydrocarbons

Hydrocarbons are compounds that have mainly carbon, hydrogen and other elements.

Saturated hydrocarbon

• These hydrocarbons have single bond between carbon atoms.
• They are less reactive.
• They burn with blue flame.
• Examples: alkanes (methane, ethane)

Unsaturated hydrocarbons

• These hydrocarbons have double and triple bonds between carbon atoms.
• They are more reactive.
• They burn with yellow sooty flame.
• Examples: Alkenes and alkynes

Chains, Branches, Rings and Isomerism

Carbon atoms can join with each other in different ways because of catenation. Due to these compounds have straight chain, branched chain and ring structures.

Straight chain compounds (Open chain)

Carbon atoms are connected one after another in a single line.

Examples: methane, ethane, propane

  CH₃ - CH₃   ,    CH₂ = CH₂  

This is called a normal (n) structure.

Branched chain compounds

These compounds have a side carbon branch attached to the main chain.

Example: Butane

Butane can be arranged in two different ways

n- butane and iso butane (2-methyl propane)

 

                  

(n-butane)                (iso butane)

Bothe have the same molecular formula but different structures.

Ring Structured Compounds (Cyclic)

Carbon atoms join to form a closed ring, these are called cyclic compounds.

Examples: cyclohexane – it has six carbon atoms forming a ring with single bonds.

Benzene

Benzene has 6 carbon atoms.

It has ring structure.

Six carbon atoms form a ring with alternating double bonds.

It is called aromatic compounds (have a particular smell)

Isomerism

The compounds that have same molecular formula but different structure. These are called isomers.

Example: Butane has two isomeric structures – (i) n-butane (ii) isobutane

These isomers have different physical properties

Functional Groups

The atoms other than carbon and hydrogen is present in carbon compounds are called heteroatoms.

When a heteroatom is attached to a carbon chain, it forms a functional group.

A functional group is the active part of an organic molecule that decides its chemical properties and reactions.

Homologous Series

• It is the series of compounds with same functional group.

• Successive members of series differ by -CH₂ unit.

• Each member of homologous series show similar chemical properties.

Example: Alcohol Series – CH₃OH, C₂H₅OH , C₃H₇OH

General Formula of Hydrocarbons

Alkanes – C_nH_2n+2

Alkene – C_nH_2n

Alkynes - C_nH_{2n -2}

Nomenclature of Carbon Compounds (Hydrocarbons)

Naming of carbon compounds in a homologous series is based on:

The basic carbon chain name

Add a prefix or suffix to show the functional group

Steps to Name a Carbon Compound

(i)        Count the number of carbon atoms in the longest chain

       

No. of carbon atoms	prefix
1	Meth
2	Eth
3	Prop
4	But

 

(ii)       Identify the functional group (if present): This is added as prefix or suffix to the base formula

     

Functional group	Prefix /suffix
Halo group	Chloro,bromo (prefix)
Alcohol	Ol (suffix)
Aldehyde	Al (suffix)
Ketone	One (suffix )
Carboxylic acid	Oic acid (suffix)

 

(iii)      Rule for adding suffix: if the suffix of the functional group starts with a vowel, then remove the final ‘e’ from the base name and add suffix.

Chemical Properties of Carbon Compounds

      1. Combustion

   

     ·     Carbon compounds burn in oxygen to produce carbon dioxide, water and heat.

          CH₄ + O₂ →CO₂ + H₂O +heat

 ·     Saturated hydrocarbons burn with blue flame.

 ·     Unsaturated hydrocarbons burn with yellow sooty flame.

·     Coal and petroleum release pollutants like SO₂. NO₂

 

    2. Oxidation

    ·     Ethanol is converted to ethanoic acid when heated in the presence of alkaline KMnO₄ / acidic K₂Cr₂O₇.

    ·     Substances that add oxygen to other substances are called oxidizing agents.

    3. Addition Reaction

    ·     Unsaturated hydrocarbons undergo this reaction.

    ·     Hydrogen is added to unsaturated hydrocarbons in the presence of catalyst.

    ·     The reaction is used in the hydrogenation of vegetable oil in the presence of nickel catalyst for making vegetable ghee.

    4. Substitution Reaction

    ·     Saturated hydrocarbons undergo this reaction.

     ·     In the presence of sunlight, chlorine displace hydrogen one by one.

  

 

  

 

  

 

  

 

Important Carbon Compounds

(i)         Ethanol (ii) Ethanoic acid 

 

(i)      Ethanol (Ethyl alcohol)

Formula: C₂H₅OH

Uses: used as solvent, in medicines, alcoholic drinks

Chemical reaction of ethanol

i.  Reaction with sodium

   2Na + 2CH₃CH₂OH → 2CH₃CH₂O^-Na⁺ + H₂

ii.   Dehydration of ethanol

 

(ii)    Ethanoic acid

Formula – CH₃COOH

Properties

    ·     It is weak acid.

    ·     It freezes in winter so it is called glacial acid.

    ·     Its 5-8% solution called vinegar.

Chemical reaction of ethanoic acid

i.     Esterification: ethanoic acid reacts with ethanol in the presence of acid to give an ester.

   

ii.  Reaction with base

   NaOH + CH₃COOH → CH₃COONa + H₂O

iii.       Reaction with sodium carbonate and sodium hydrogen carbonate

  CH₃COOH + Na₂CO₃ → 2CH₃COONa + H₂O +CO₂

 CH₃COOH + NaHCO₃ → CH₃COONa + H₂O +CO₂

Soap and Detergents

Soap: These are sodium or potassium salts of long chain carboxylic acids. Soap molecule has water loving end called hydrophilic end and oil loving end called hydrophobic end.

Detergent: These are ammonium or sulphonate salts of carboxylic acids. They work effectively with hard water.

Micelle Formation

A cluster of molecules in which the hydrophobic tails are in the interior of the cluster and the ionic ends are on the surface of the cluster, this formation is called a micelle. This removes dirt during washing.

Conclusion

This quick revision notes of carbon and its compounds is useful of RBSE Class 10 students because it is designed for quick revision and based on NCERT Science text books and syllabus.

  Related Topics

_{1.  Chemical reactions and Equations Quick Revision Notes}

2. Acids, Bases and Salts Quick Revision Notes 

3. Metals and Non-metals Quick Revision Notes

Frequently Asked Questions

Q1. Why is carbon able to form a large number of compounds?

Answer

Carbon has two properties – catenation and tetravalency.so carbon form long chains, branches and rings and stable covalent bonds.

Q2. What is isomerism?

Answer

Isomerism is a phenomenon where compounds have eh same molecular formula but different structures.

Q3. What is the role of a functional group in a carbon compound?

Answer

A functional group is the active part of the molecule that determines its chemical properties, reactions and naming.

Q4. Why does graphite conduct electricity but diamond does not?

Answer

Graphite has one free electron, so it conducts electricity while diamond has four valence electrons are bonded so it does not conduct electricity.

Q5. What is micelle?

Answer

Micelle is a cluster of soap molecules where hydrophobic end trap dirt and hydrophilic head remain outside in water.