Back to Lesson

• Bonding in carbon: Carbon contain 4 electron in outermost shell. It requires large energy to donate 4 electrons and attain stability or noble gas configuration. Hence, carbon share its electron forming covalent bond.
• Types of covalent bond:
• Single covalent bond: Bond formed by sharing of two electrons. E.g. methane.
• Double covalent bond: Bond formed by sharing of four electrons. E.g ethene.
• Triple covalent bond: Bond formed by sharing of six electrons. E.g. ethyne.
• Allotropes of carbon: Carbon occur in different forms like diamond, graphite and fullerenes.

Allotropes of carbon	Bonding	Structure	Physical property	Electrical conduction
Diamond	Each carbon bonded with 4  other carbon		Very hard	No conduction
Graphite	Each carbon bonded to 3 other carbon in same plane		Soft, slippery, easily breakable	Good Conductor
Fullerenes	In fullerene C-60, carbon atoms are arranged in football like structure		Soft and slippery	Bad Conductor

• Nature of carbon:
• Carbon has ability to form long chain of carbon atoms. This is known as property of catenation.
• Carbon compound can be straight chain, branched chain or can be in ring structure.
• Carbon compounds are linked with single, double and triple bond. Carbon compounds with single bond are saturated compounds. Carbon compounds with double or triple bonds are unsaturated compounds.
• Valency of carbon is four, hence it can form bond with four carbon or other four elements. Each compound differs in physical and chemical properties. E.g. diamond is hard/ solid while methane(CH4) is gas.
• Saturated Carbon Compound: They are linked with single bond. Single bond between carbon carbon can be represented by dash or by electron dot structure.

• Unsaturated Carbon Compounds: They are linked with double or triple bond. Carbon carbon bonding can be represented by double dash  or triple dash in a dash structure or by electron dot structure.   

• Chains, Branches and Rings: Carbon compounds contains long straight chain of atoms, or branch of carbon atom in chain or ring like structure.Carbon atom with same molecular formula and different structural formula are structural isomers. Chain / Branch / Rings may be saturated or unsaturated.
• Hydrocarbons: Compounds containing carbon and hydrogen.

Hydrocarbon	Bond	Known as / General formula	Example
Saturated	Single bond	Alkanes   /   (CnH2n+2)	Methane, ethane, propane,etc.
Unsaturated	Double bond	Alkenes   /   (CnH2n)	Ethene, propene, butene, etc.
	Triple bond	Alkynes   /   (CnH2n-2)	Ethyne, propyne, butyne, etc.

• Other Carbon Compounds: other than hydrogen carbon forms bonds with oxygen, nitrogen, sulphur and halogens(Fluorine, Chlorine, Bromine, Iodine). Elements replacing hydrogen atoms are called heteroatom. It gives specific properties to carbon compound, hence are called functional group (Alcohol -OH, Halo -Cl/-Br/-I, Ketone  -CO, Carboxylic Acid -COOH).
• Homologous series: Series of compound having same functional group.     
• Nomenclature of Carbon Compounds:  [Refer the video to understand in detail]

1. Select longest chain of carbon atoms and identify the parent alkane.

CH3-CH2-CH2-CH2-OH.  Parent alkane: butane

1. Identify the functional group.

CH3-CH2-CH2-CH2–OH.     Functional group: Alcohol i.e. OH (-ol)

1. Number the carbon atom in chain such that, carbon atom attached to functional group gets lowest number.

   

1. Name the compound by replacing ‘e’ of  parent alkane with name of functional group.

CH3-CH2-CH2-CH2–OH Compound name: butanol

1. Compound name should indicate position of functional group.

Compound name: butan-1-ol

1. For unsaturated chain, ‘ane’ is replaced by  ‘ene’ or ‘yne’ according to the bond. E.g. propyne, butyne, hexene.
2. Some functional groups are:

Functional groups	Prefix / Suffix
Halogen	Prefix: chloro- , bromo- , etc
Alcohol	Suffix: -ol
Aldehyde	Suffix: -al
Ketone	Suffix: -one
Carboxylic Acid	Suffix: -oic acid
Alkenes	Suffix: -ene
Alkynes	Suffix: -yne

• Chemical properties of carbon compounds:
• Combustion: Produces carbon dioxide and releases heat and light.

1. Saturated hydrocarbons: Burns with clean blue flame.
2. Unsaturated hydrocarbons: Burns with yellow flame and black smoke.    
1. Formation of coal and petroleum: coal , petroleum are obtained from fossils, they are known as fossil fuels. Form by following process.  
2. Oxidation: Ethanol is oxidised in presence of heat and potassium permanganate or acidified potassium dichromate to form acetic acid.

         

• Addition Reaction: Unsaturated hydrocarbon are converted to saturated hydrocarbon by addition of hydrogen in presence of Nickel or Palladium catalyst. E.g. vegetable oil converted to saturated hydrocarbon.

• Substitution Reaction: One atom or group of atoms replaced with another.

•  Ethanol:

Properties	Liquid at room temperature Good solvent Soluble in water
Uses	Used in alcoholic drinks Used in medicines (tincture iodine, cough syrups, tonics) Used as additive to petrol
Effects	Pure ethanol if consumed causes harmful effects on body Disturbs metabolic processes Lack of coordination by mind
Reaction	Reaction with sodium releases hydrogen gas.            Dehydration of ethanol produces ethene.

• Ethanoic acid / Acetic acid:

Properties	Weak acid Freezes below 290 K (also called glacial acetic acid) It is carboxylic acid
Uses	Used as preservatives in form of vinegar(5-8% of acetic acid).
Reactions	Esterification reaction:            Saponification Reaction:            On reaction with base forms salt and water. Carbonates and Hydrogen Carbonates:

• Soap: Soap is sodium or potassium salt of carboxylic acid. Molecules of soap have two ends hydrophilic end (Na+ / K+) and hydrophobic end (long chain of carboxylic acid). Dirt is oily in nature hence, the hydrophobic end dissolves it and orient inward, whereas, the hydrophilic end is oriented away from dirt. Hence, a micelle structure is formed.  Due to ion ion repulsion micelles don’t come together, and can be easily rinsed with water.
• Detergent: In hard water, soap do not produce lather, but it forms precipitate with calcium and magnesium salts from water. Detergents are ammonium or sulphonate salts of carboxylic acids which are effective in hard water and do not form precipitate. They are used to make shampoos and products for cleaning clothes.