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PREPARED BY

RAMACHANDRAPPA B.T, PGT CHEMISTRY

JAWAHAR NAVODAYA VIDYALAYA BALEHONNUR

CHIKKAMAGALUR DIST., KARNATAKA - 577112

NAVODAYA VIDYALAYA SAMITI, NOIDA

E-CONTENT FOR CLASS X SCIENCE

CARBON AND ITS COMPOUNDS

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some interesting facts about carbon

Carbon is an element, belong to non-metal and its symboI is ”C”
The name of the ‘Carbon’ derived from the Latin word “Carbo’ which means coal. This is because carbon is the main constituent of coal.
It is the fourth most abundant element in the universe
H He O C
PPM 739000 240000 10400 4600
It is the 15^th most abundant element in earth’s crust
O > Si > Al > Fe> Ca > Na > K > Mg > Ti > H
It is 2^nd abundant element in the human body
O C H N Ca P K
65% 18% 10% 3% 1.5% 1.2% 0.2%
Carbon is found in the atmosphere (0.03%) as Carbon dioxide.
Inside the earth’s crust (0.02%) as Minerals (like carbonates, coal & petroleum)
In all living organisms as organic compounds
Carbon is found in the free state as diamond, graphite & fullerenes.

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Importance of carbon compounds

Foods - starch, sugar, fats, vitamins, proteins
Fuels - wood, coal, alcohol, petrol
Poisons - opium, strychnine
Drugs and disinfectants - penicillin, quinine, aspirin, sulpha drugs
Household and commercial articles -paper, soap, cosmetics, oils, paints
Textile fabrics - cotton, wool, silk, linen, rayon, nylon
Perfumes - vanillin, camphor
Dyes - indigo, congo red, malachite green
War gases - mustard gas, chloropicrin, lewisite
Explosives - nitroglycerine, dynamite, picric acid, TNT

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Organic Chemistry

🔾 Study of Carbon Compounds

The word organic means ‘Living origin’

It was believed that carbon compounds can be prepared by living things only.

This theory is known as Vital Force Theory

In 1828 Friedrich Wohler blown up this theory by preparing Urea(purely organic) by heating Ammonium Cyanate NH₄CNO (purely inorganic)

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Why study of Carbon Compounds is a separate branch of Chemistry?

It is due to the vastness in the number of Carbon Compounds

Carbon with other elements such as H,N,O,F Cl,Br,I,S… forms more than 5 million compounds

The other elements altogether forms about 70,000 compounds only

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Reason for the wastness in number of carbon compounds

Bonding in carbon compounds

Catenation

3. Isomerism

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Bonding in carbon compounds-Covalent bonding

The atomic number of carbon is 6, Its electronic arrangement is 2,4 or (K₂L₄).

It has 4 valence electrons.
It can attain stability by gaining 4 electrons or loosing 4 electrons or sharing 4 electrons with other atoms.
But …
It does not gain 4 electrons because it is difficult for the 6 protons to hold 10 electrons.
It does not loose 4 electrons because it need large amount of energy to loose 4 electrons.

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Hence
It shares 4 electrons with other atoms to attain stability resulting in the formation of covalent bonds.
Since carbon atoms needs 4 electrons to attain stability, its valence is 4 and it is tetravalent.

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Formation of Covalent Bond

Covalent bond is chemical bond formed by the sharing of electrons between atoms.

The Sharing of one pair electrons results in the formation of single covalent bond.

Sharing of Two pairs electrons results in the formation of double covalent bond.

And Sharing of Three pairs electrons in the formation of triple covalent bond.

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Formation of Single Bond

Ex : Formation of single covalent bond in Hydrogen molecule H₂

The atomic number of Hydrogen is 1, its electronic arrangement is 1, it has 1 valence electron it need one electron more to attain stability. So 2 hydrogen atoms share 1 pair electrons resulting in the formation of single covalent bond in hydrogen molecule H₂.

H ^x+ ^xH 🡪

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Formation of Double Covalent Bond

Ex : Formation of double covalent bond in oxygen molecule O₂

The atomic number of Oxygen is 8, its electronic arrangement is 2,6, it has 6 valence electron it needs two electrons more to attain stability. So 2 oxygen atoms share 2 pairs electrons resulting in the formation of double covalent bond in oxygen molecule O₂.

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Formation of Triple Covalent Bond

Ex : Formation of triple covalent bond in Nitrogen molecule N₂

The atomic number of Nitrogen is 7, its electronic arrangement is 2,5, it has 5 valence electron it needs three electrons more to attain stability. So 2 nitrogen atoms share 3 pairs of electrons resulting in the formation of triple covalent bond in nitrogen molecule N₂.

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Carbon atom can form multiple �covalent bonds

If sufficient number of other atoms are not there…

In order to satisfy the four valences carbon form double or triple bond between two C atoms

ETHANE

ETHENE

ETHYNE

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Catenation

Carbon atom can form bonds with other carbon atoms to form a long chains, branched chain and closed rings. This property is called Catenation.

NORMAL BUTANE (C₄H₁₀) ISO BUTANE (C4H₁₀)

Long chain Branched chain

CYCLOHEXANE (C₆H₁₂)

Closed ring

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Since valency of carbon is 4, it can form bonds with other carbon atoms or with atoms of other elements like Hydrogen, Oxygen, Nitrogen and Halogens etc.,

Chloromethane Di Chloromethane Tri Chloromethane Tetra Chloromethane

CH₃Cl CH₂Cl₂ CHCl₃ CCl₄

Carbon Disulphide Carbon Dioxide Urea

CS₂ CO₂ CO(NH₂)₂

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Isomerism

Compounds having same molecular formula but different structures are known as Isomers and this phenomenon is called Isomerism

Ex : Butane – C₄H₁₀ has 2 isomers. They are Normal Butane and isobutane.

Normal butane C₄H₁₀ Isobutane C₄H₁₀

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Isomerism

Compounds having same molecular formula but different structures are known as Isomers and this phenomenon is called Isomerism

Ex : Butene – C₄H₁₀ has 2 isomers. They are Normal Butane and isobutane.

Normal butane C₄H₁₀ Isobutane C₄H₁₀

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Ex : Pentane – C₅H₁₂ has 3 isomers. They are normal pentane, isopentane and neopentane.

Normal pentane C₅H₁₂ Isopentane C₅H₁₂

Neopentane C₅H₁₂

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Isomers of Hexane

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Hydrocarbons

Organic compounds containing carbon and hydrogen only

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Classification of Hydrocarbons

OPEN CHAIN -ALLIPHATIC

CLOSED CHAIN

SATURATED

UN SATURATED

ALICYCLIC

AROMATIC

ALKANES-SINGLE BONDED

ALKENES-DOUBLE BONDED

ALKYNES-TRIPLE BONDED

HYDROCARBON

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Saturated Hydrocarbons : A hydrocarbon in which carbon atoms are connected by only single bonds is called a saturated Hydrocarbons.

Saturated Hydrocarbons are also called Alkanes.

The general formula of hydrocarbons or Alkanes is C_nH_2n+2. Where n is the number carbon atoms in 1 molecule of alkane

Ex : If n = 1 ; CH₄ If n = 2 ; C₂H₆

If n = 3 ; C₃H₈ If n = 4 ; C₄H₁₀….

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Unsaturated Hydrocarbons (Alkenes and Alkynes) : A hydrocarbon in which the two carbon atoms are connected by a “double bond” or “triple bond” is called unsaturated hydrocarbon.

Ex : Alkenes and Alkynes :

Alkenes : An unsaturated hydrocarbon in which the two carbon atoms are connected by a “double bond” is called an Alkene.

The general formula of an Alkene is C_nH_2n Where n is number of carbon atoms in its one molecule.

If n = 2 C₂H₄Ethene n = 3 C₃H₆Propene

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Alkynes : An unsaturated hydrocarbon in which the two carbon atoms are connected by a “triple bond” is called an Alkyne.

The general formula of an Alkyne is C_nH_2n-2 Where n is number of carbon atoms in its one molecule.

If n = 2 ; C₂H₂Ethyne n = 3 ; C₃H₄Propyne

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Alkyl group: The group formed by the removal of one hydrogen atom from an alkane molecule is called an Alkyl group

Ex :

Methyl group (CH₃-)

Ethyl group (C₂H₅-)

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Nomenclature of open chain Hydrocarbons

According to International Union of Pure and Applied Chemistry(IUPAC)
The name consists of two parts
Indicating number of Carbon atoms-’Alk’part

2)Indicating the type of bonding-’Primary suffix’

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‘Alk ‘ part

No. of C atoms	‘Alk’ part
1	Meth
2	eth
3	Prop
4	But
5	Pent
6	Hex
7	Hept
8	Oct
9	Non
10	Dec

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Primary Suffix

If all the bonds are single bond ‘ane’

If one double bond ‘ene’

If one triple bond ‘yne’

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Thus

Single bonded compounds have the name- Alk+ane =Alkane
Double bonded compounds have the name- Alk+ene =Alkene
Triple bonded compounds have the name- Alk+yne =Alkyne

Example

No of carbon atom=4

alk part is but

All the C-C bonds are single bond

primary suffix is ane

Therefore the name is butane

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Nomenclature of compounds �containing functional group

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Homologous Series

Homologus series is a group of carbon compounds having similar structure, similar chemical properties and whose successive members is differ by a –CH₂ group

Homologous Series of
Alkanes	Alkenes	Alkynes
CH₄ C₂H₆ C₃H₈ C₄H₁₀	C₂H₄ C₃H₆ C₄H₈ C₅H₁₀	C₂H₂ C₃H₄ C₄H₆ C₅H₈

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Homologous Series of
Aldehydes	Alcohols	Carboxylic acids
HCHO CH₃CHO C₂H₅CHO C₃H₇CHO	CH₃OH C₂H₅OH C₃H₇OH C₄H₉OH	CH₃COOH C₂H₅COOH C₃H₇COOH C₄H₉COOH

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allotropes of carbon

“The various physical forms in which an element can exist are called allotropes of the elements”.

The carbon element exist in three solid forms called allotropes. They are

1) Diamond 2) Graphite 3) Buckminster fullerene

Diamond & graphite are two common allotropes of carbon which are known to us for centuries, Buckminster fullerene is the new allotrope of carbon which has been discovered recently

The properties of diamond & graphite are well known but the properties of Buckminster fullerene are still being investigated.

All the allotropes of carbon burns on strong heating to form carbon dioxide, and the formed carbon dioxide gas if it pass through lime water. It turns to milky, It shows that all the allotropes of carbon contain carbon.

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diamond

Diamond is a colourless transparent substance having extraordinary brilliance.
Diamond is quite heavy and extremely hard
It is the hardest natural substance known in the nature
Diamond does not conduct electricity

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structure of diamond

Each carbon atom in the diamond crystal is linked to four other carbon atoms by strong covalent bonds, the four surrounding Carbon atoms are at the four corners of a regular tetra hedron and which are powerfully bonded to one another forms a network of covalent bonds, due to this diamond structure is very rigid. This rigid structure make it very hard, and also responsible for High density and melting point.

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Diamond is a non conductor of electricity

Carbon atom has 4 valence electron in it. In a diamond crystal, each carbon atom is linked to 4 other carbon atoms by covalent bonds, and hence all the 4 valence electrons of each carbon atom are used up in forming the bonds. Since there are “ no free electrons” in a diamond crystal, it does not conduct electricity.
Diamonds can be made artificially by subjecting pure carbon to very high pressure & temperature. These are called synthetic diamonds.
synthetic diamonds are small but are otherwise indistinguishable from natural diamonds.

uses of diamonds:

In glass cutter
For making Jewellery
A sharp, diamond edged knife (called keratoma) is used by eye surgeons to remove cataract from eye.
As diamond studded saws & drill bits.

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GRAPHITE

GRAPHITE STRUCTURE

Each carbon atoms in a graphite layer is joined to three other carbon atoms by strong covalent bonds to form flat hexagonal rings structure called ”Array”. The various layers of carbon atoms in graphite are quite far apart so that no covalent bonds can exist between them. The various layers of carbon atoms in graphite are held together by weak Vander waals forces. Since the various layers of carbon atoms in graphite are joined by weak forces. They can slide over one another.

Due to the sheet like structure graphite is a comparatively soft substance. It is the softness of graphite which makes it useful as a dry lubricant for machine parts.

Graphite is a good conductor of electricity it is because in a graphite crystal. Each carbon atoms is joined to only three other carbon atoms by covalent bonds, Thus only the three valence electrons of each carbon atoms in graphite are used in bond formation. The fourth valence electron of each carbon atom is “free” to move

Due to the “presence of free electrons” in a graphite crystal, it conducts electricity.

Like diamond, graphite also has very high melting point.

The structure of graphite is very different from that of diamond. A graphite crystal consists of layers of Carbon atoms.

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USES OF GRAPHITE

Due to its softness used as lubricants both dry and wet forms

Graphite is good conductor of electricity due to which graphite is used for making carbon or graphite electrode in dry cells & electric arcs.

Graphite is used in making pencil leads.

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BUCK MINISTER FULLERENE

It is a dark solid at room temperature
It differs from the other two allotropes of carbon, diamond & graphite are giant molecules which consists of an unending network of carbon atoms but buckminsterfullerene is very small molecule made up of only 60 carbon atoms.
Diamond is extremely hard where as graphite is soft. On the other hand, buckminsterfullerene is neither very hard nor soft.
Other properties of buckminsterfullerene are still being investigated.

Buckminster fullerene is an allotrope of carbon containing clusters of 60 carbon atoms joined together to form spherical molecules

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Deleted Portion

The content in the slide no. from 47 - 59deleted for the academic year 2020-2021

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Chemical Properties of Carbon Compounds

Combustion-Burning in oxygen
Gives oxides
Exothermic-produces heat and also light
Saturated compounds give a clean flame while unsaturated compounds give sooty flame

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Oxidation

Oxidation –Addition of oxygen

Example

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Addition Reactions

A molecule add to another molecule by breaking of bonds
Unsaturated hydrocarbon add hydrogen in presence of catalyst such as Palladium or Nickel

This reaction is used in the hydrogenation of vegetable oils

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Substitution reactions

An atom or a group replaces another atom or group in a compound

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ETHANOL-CH₃CH₂OH

Ethanol is a liquid at room temperature
It is the active ingredient of all alcoholic drinks
It is a good solvent-therefore it is used in medicines such as Tincture of Iodine , Cough syrups , Tonic…

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Reactions

With sodium-

Reaction to give unsaturated Hydrocarbon-with conc H₂SO₄ at 443K

Involve removal of water and is called Dehydration

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Ethanoic acid -CH₃COOH

Commonly known as Acetic acid
5-10%solution of acetic acid is called Vinegar
Vinegar is a preservative for pickles
Its melting point is 290K

It freezes in cold climate-therefore known as Glacial acetic acid

It is a weak acid

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