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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

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

Methane(CH4)

In this compound one carbon atom is covalently bonded
to 4 hydrogen atoms

C(2,4)

Electron-dot cross
structure

Structural formula

Molecular formula
H(1)

Oxygen molecule(O2) contains 2 covalently bonded
oxygen molecule.

O(2,6)

Electron-dot cross
structure

Structural formula

Molecular formula
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Nitrogen molecule(N2) contains 2 covalently bonded
nitrogen atoms
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N(2,5)

Electron-dot cross
structure

Structural formula
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Molecular formula
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Tetra valency
C(2,4) shows valency = 4
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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
struture

Eg
branched chain
network like

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
GRAPHITE
DIAMOND
Physical
properties
It is soft, grayish
black crystalline
substance
It is a hard, beautiful
crystalline substance
Structure
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
Conduction of
electricity
Good conductor
Uses
Is used in making
electrodes and
lead pencils and
as a lubricant
Non conductor
Is used as precious stone
in jewellery
BLACK DIAMONDS are
used for cutting glass

The compounds containing carbon and hydrogen only
are called as hydrocarbons.
CLASSIFICATION OF HYDROCARBON
Hydrocarbon
Closed Chain
Open Chain
Unsaturated
Saturated
Alkane
C-C
Alkene
C=C
Alkyne
C≡C
ane
Single bond
GF: CnH2n+2
Eg: Methane
MF: CH4
SF:
Eg: Ethane
MF:C2H6
SF:
Eg:Propane
MF: C3H8
SF:
ene
double bond
CnH2n
Ethene/Ethylene
C2H4
Propene
C3H6
yne
triple bond
CnH2n-2
Ethyne/Acetylene
C2H2
Propyne
C3H4
Eg: Butane
MF: C4H10
SF:
Eg: Pentane
MF: C5H12
SF:
Eg: Hexane
MF: C6H14
SF:
Eg: Heptane
MF: C7H16
SF:
Butene
C4H8
Butyne
C4H6
Pentene
C5H10
Pentyne
C5H8
Hexene
C6H12
Hexyne
C6H10
Heptene
C7H14
Heptyne
C7H12
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
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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
Their carbon skeleton:
C
branched chain
The compounds which have closed chain of carbon
atoms are known as Closed Chain Compounds.
 Eg: Cyclohexane
MF: C6H12
SF:

carbon skeleton
complete molecule
Structure of BENZENE:
MF: C6H6
SF:
TYPE OF
FUNCTIONA
COMPOUND L GROUP
GENERAL
FORMULA
Alcohols
R-OH
Methyl alcohol
(where,
R=alkyl grp) Ethyl alcohol
CH3-OH
R-CHO
(where,
R=H (or)
alkyl grp)
Methyl aldehyde
H-CHO
Ethyl aldehyde (or)
Acetaldehyde
CH3-CHO
R-C-R
(where, R=
alkyl grp)
Dimethyl ketone (or)
Acetone
=
O
-C-H
O
=
Ketones
-C-
C2H5-OH
O
=
-CHO
FORMULA
CH3-C-CH3
Ethyl methyl ketone
O
=
Aldehydes
-OH
Eg
NAME
C2H5-C-CH3
-COOH
0
=
Carboxylic
acid
-C-OH
R-COOH
(where,
R=H (or)
alkyl grp)
Methanoic acid
(or) Formic acid
H-COOH
Ethanoic acid
(or)Acetic acid
CH3-COOH
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The atom or group of atoms present in a
molecule which determines characteristics
property of organic compounds is called the
Functional Group.
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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.
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Eg Homologous series of Alkanes(GF: CnH2n+2)
ALKANES
MF
METHANE
CH4
ETHANE
C2H6
PROPANE
C3H8
BUTANE
C4H10
PENTANE
C5H12
ALCOHOLS
MF
METHYL ALCOHOL
CH3-OH
ETHYL ALCOHOL
C2H5-OH
PROPYL ALCOHOL
C3H7-OH
BUTYL ALCOHOL
C4H9-OH
Important characteristics of
homologous series
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The GF of all compounds in the series is the same.

They have same functional group
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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
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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
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Prefix: the no of the carbon atom to which the suffix is
attached
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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
CO2 + 2H2O + heat and light

CH4 + O2

2C4H10 + 13O2
8CO2 + 10H2O + 2658KJ heat
In limited supply of air

CH4 + O2
C + 2H2O
carbon black
Note:
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Saturated hydrocarbons always burns with BLUE flame called
OXIDISING flame
Unsaturated hydrocarbon always burns with YELLOW flame called
REDUCING flame
The reaction in which two molecules reacts to form a
single product is known as Addition Reaction
Eg:

H – C = C – H + Br – Br
–
–
H H
H–C–C–H
–
–
–
–
H H
Br Br
1,2-Dibromoethane (or)
Ethylene dibromide

Eg
The reaction where one or more atoms are
replaced by one or more other atoms is called as a
Substitution Reaction
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MF:C2H5OH
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LF: CH3CH2OH
Physical properties:
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A colourless liquid,
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Pleasant odour
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BP=78oC and FP= -114oC
Chemical properties of Ethyl alcohol:
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It is combustible and burns with blue flame
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2C2H5OH + 2Na
2C2H5Na + H2
3C2H5OH + PCl3
Sodium ethoxide
3C2H5Cl + H3PO3
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Phosphorous
Ethyl
trichloride
chloride
Phophorous
acid
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MF:CH3COOH
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LS: CH3COOH
Physical properties:
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It’s a weak acid
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Pungent smell ,colourless ,corrossive liquid
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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 + HCl
Monochloroacetic acid
CH2ClCOOH + Cl2
CHCl2COOH + HCl
Dichloroacetic acid
CHCl2COOH + Cl2
CCl3COOH + HCl
Trichloroacetic acid
Reaction with metal like sodium
2CH3COOH + 2Na
2CH3COONa + H2
Sodium acetate
Reaction with alcohol
CH3COOH + C2H5OH
CH3COOC2H5 + H2O
Ethyl acetate
(Ethyl methyl ester)
TOILET SOAP
LAUNDRY SOAP
Raw 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