Amazing World of Carbon Compounds

Introduction At the beginning of 19th century organic compounds

were defined as Compounds directly or indirectly obtained from plants

and animals are called as organic compounds Compounds obtained from minerals are called as

inorganic compounds A change in defination took place by synthesis of an

organic compound from an inorganic compound WOHLER converted Ammonium cyanate to Urea (inorganic compd) (org compd) New defination

Compounds containing covalently bonded carbon atom or atoms are called as organic compounds

Carbon is covalently bonded with hydrogen oxygen, halogens, and sometimes with nitrogen and sulphur.

Carbon atomic no 6 shows EC :s 2,4

Valency = 4

Similarly

Nitrogen’s valency = 3

Oxygen’s valency = 2

Hydrogen valency = 1

Properties of Organic Compounds

They have low melting and boiling points

They are generally insoluble in water but soluble in organic solvents

They are poor conductors of heat and electricity

Formation Of Methane Methane(CH4)

In this compound one carbon atom is covalently bonded to 4 hydrogen atoms

C(2,4) H(1)

Electron-dot cross

structure

Structural formula

Molecular formula

Formation of Oxygen Molecule Oxygen molecule(O2) contains 2 covalently bonded

oxygen molecule.

O(2,6)

Electron-dot cross

structure

Structural formula

Molecular formula

Formation of Nitrogen Molecule Nitrogen molecule(N2) contains 2 covalently bonded

nitrogen atoms

N(2,5)

Electron-dot cross

structure

Structural formula

Molecular formula

Carbon Forms Infinite no of Compounds

Tetra valency

C(2,4) shows valency = 4

Multiple bonding

It can form carbon to carbon

Single bond C - C

Double bond C = C

Triple bond C ≡ C

Catenation The property of direct bonding between atoms of same

element to form a chain is known as catenation.

The remarkable property of carbon atom to form bonds with itself and give rise to a single large struture or chain is called catenation.

The chain can be straight chain, branched chain or may have network like structure

Straight chain branched chain network like struture

Eg

Allotropes of Carbon

The phenomenon of existence of a substance in various

physical forms but same chemical form is known as

Allotropy.

DIAMOND and GRAPHITE are the allotropes of carbon

Physical properties

Structure

Conduction of electricity

Uses

It is soft, grayish black crystalline

substance

It is a hard, beautiful crystalline substance

It has a hexagonal planer structure,

where each carbon atom is attached to

3 other carbon atoms

It has a regular tetrahedron structure,

where each carbon atom is linked to 4

other carbon atoms

Good conductor Non conductor

Is used in making electrodes and

lead pencils and as a lubricant

Is used as precious stone in jewellery

BLACK DIAMONDS are used for cutting glass

GRAPHITE DIAMOND

Hydrocarbon The compounds containing carbon and hydrogen only

are called as hydrocarbons.

CLASSIFICATION OF HYDROCARBON

Hydrocarbon

Open Chain Closed Chain

Saturated Unsaturated

Alkane Alkene AlkyneC-C C=C C≡C

ALKANE ALKENE ALKYNEane ene yne Single bond double bond triple bondGF: CnH2n+2 CnH2n CnH2n-2

Eg: MethaneMF: CH4

SF:

Eg: Ethane Ethene/Ethylene Ethyne/AcetyleneMF:C2H6 C2H4 C2H2

SF:

Eg:Propane Propene PropyneMF: C3H8 C3H6 C3H4

SF:

Eg: Butane Butene ButyneMF: C4H10 C4H8 C4H6

SF:Eg: Pentane Pentene PentyneMF: C5H12 C5H10 C5H8

SF: Eg: Hexane Hexene HexyneMF: C6H14 C6H12 C6H10

SF:Eg: Heptane Heptene HeptyneMF: C7H16 C7H14 C7H12

SF:

ALKANE ALKENE ALKYNE

PROPERTIES ALKANE ALKENE ALKYNE

General formula CnH2n+2 CnH2n CnH2n-2

No of hydrogen atoms

2 more than resp alkene and 4 more than resp alkyne

2 less than resp alkane and 2 more than resp alkyne

4 less than resp alkane and 2 less than resp alkene

Reactivity Least Medium High

They undergo Substitution reaction

Addition reaction Addition reaction

Isomerism The property of compounds to have same molecular

formula but different structural formulae is known as Isomerism.

Compounds with same molecular formula but different structural formulae are called as isomers.

Eg: Pentane

MF: C5H12

SF:

Straight chain branched chain

Their carbon skeleton:

C

Closed Chain Compounds The compounds which have closed chain of carbon

atoms are known as Closed Chain Compounds. Eg: CyclohexaneMF: C6H12

SF:

carbon skeleton complete moleculeStructure of BENZENE:MF: C6H6

SF:

Functional GroupsTYPE OF COMPOUND

FUNCTIONAL GROUP

GENERAL FORMULA

EgNAME

FORMULA

Alcohols -OH R-OH(where, R=alkyl grp)

Methyl alcohol CH3-OH

C2H5-OH

Aldehydes -CHO O-C-H

R-CHO(where, R=H (or) alkyl grp)

Methyl aldehyde

Ethyl aldehyde (or) Acetaldehyde

H-CHO

CH3-CHO

Ketones O -C-

R-C-R(where, R= alkyl grp)

Dimethyl ketone (or) Acetone

Ethyl methyl ketone

O

CH3-C-CH3

O

C2H5-C-CH3

Carboxylic acid

-COOH 0-C-OH

R-COOH(where, R=H (or) alkyl grp)

Methanoic acid(or) Formic acid

Ethanoic acid (or)Acetic acid

H-COOH

CH3-COOH

==

==

=Ethyl alcohol

The atom or group of atoms present in a molecule which determines characteristics property of organic compounds is called the Functional Group.

Homologous Series A group of organic compounds containing same

functional group, which can be represented by the same general formula and which more or less show similar trends in their properties is known as Homologous series.

Eg Homologous series of Alkanes(GF: CnH2n+2)

ALKANES MFMETHANE CH4

ETHANE C2H6

PROPANE C3H8

BUTANE C4H10

PENTANE C5H12

Eg Homologous series of alcohol

ALCOHOLS MF

METHYL ALCOHOL CH3-OH

ETHYL ALCOHOL C2H5-OH

PROPYL ALCOHOL C3H7-OH

BUTYL ALCOHOL C4H9-OH

Important characteristics of homologous series The GF of all compounds in the series is the same.

They have same functional group

They all gradual change in their physical properties but show similar chemical propreties

Consecutive members of the series differ from one another by -CH2- group (called methylene group) and their molecular mass or weight differ by 14 units

IUPAC Nomenclature It stands for international union of pure and applied

chemistry

Terminology used in nomenclature

Root: the basic carbon skeleton

Suffix: the functional group or double or triple bond present

Prefix: the no of the carbon atom to which the suffix is attached

Chemical Properties of Carbon Compounds Combustion

The process of burning a substance in presence of oxygen is called as Combustion

All hydrocarbons when burnt in air or oxygen gives CO2 and H2O with evolution of large amount of heat

Eg

CH4 + O2

2C4H10 + 13O2

In limited supply of air

CH4 + O2

carbon blackNote: Saturated hydrocarbons always burns with BLUE flame called

OXIDISING flame Unsaturated hydrocarbon always burns with YELLOW flame called

REDUCING flame

CO2 + 2H2O + heat and light

8CO2 + 10H2O + 2658KJ heat

C + 2H2O

Addition Reaction The reaction in which two molecules reacts to form a

single product is known as Addition ReactionEg:

H H H H

H – C = C – H + Br – Br H – C – C – H

Br Br 1,2-Dibromoethane (or) Ethylene dibromide

– – – –– –

Addition of hydrogen

Substitution Reaction The reaction where one or more atoms are

replaced by one or more other atoms is called as a Substitution Reaction

Eg

Ethanol (or) Ethyl Alcohol MF:C2H5OH

LF: CH3CH2OH

Physical properties: A colourless liquid, Pleasant odour BP=78oC and FP= -114oC

Chemical properties of Ethyl alcohol: It is combustible and burns with blue flame 2C2H5OH + 2Na

Sodium ethoxide 3C2H5OH + PCl3

Phosphorous Ethyl Phophorous

trichloride chloride acid

2C2H5Na + H2

3C2H5Cl + H3PO3

Acetic Acid (or) Ethanoic Acid MF:CH3COOH

LS: CH3COOH

Physical properties: It’s a weak acid Pungent smell ,colourless ,corrossive liquid Below 290 K ,it solidfies to an ice like mass called

GLACIAL ACETIC ACID

Chemical properties of acetic acid :

Reaction with halogens

CH3COOH + Cl2

CH2ClCOOH + Cl2

CHCl2COOH + Cl2

CH2ClCOOH + HCl

Monochloroacetic acid

CHCl2COOH + HCl

Dichloroacetic acidCCl3COOH + HCl

Trichloroacetic acid

Reaction with metal like sodium 2CH3COOH + 2Na

Reaction with alcoholCH3COOH + C2H5OH

2CH3COONa + H2

Sodium acetate

CH3COOC2H5 + H2O

Ethyl acetate

(Ethyl methyl ester)

Soaps and Detergents

Soap are sodium or potassium salts of long chain carboxylic acids.

TOILET SOAP LAUNDRY SOAPRaw materials used

High quality of oils and fats are used

Cheaper quality of oils and fats are used

Perfumes added Expensive or good quality

Cheaper quality

Alkali present No free alkali present

Free alkali present