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ORGANIC
CHEMISTRY
GRADE:X
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SLO: 11.1.1: Discuss general characteristics of organic compounds.
1. Origin: Most of them come from living things (plants and animals) or from the things that were
once living (fossils).
2. Composition: Carbon is the main constituent of organic compounds. Hydrogen is also
frequently present in organic compounds. Other elements like oxygen, nitrogen, sulphur,
phosphorous and halogens are present in many organic compounds.
3. Covalent linkage: Organic compounds contain covalent bond(polar or non-polar) due to
presence of carbon atom.
4. Solubility: Organic compounds are non-polar in nature therefore mostly are soluble in organic
solvent such as ether, benzene, carbon disulphide etc. Polar organic compounds are soluble in
alcohols such as methyl alcohol and ethyl alcohol.
5. Electrical conductivity: Organic compounds are poor conductor of electricity due to presence of
covalent bond.
6. Melting and boiling point: Generally organic compounds are volatile. So they have low melting
and boiling points.
7. Stability: They are less stable as they have low melting and boiling points. 8.
Combustibility: Since organic compound possesses high percentage of carbon, they are
combustible.
9. Isomerism: Organic compounds have tendency to exhibits isomerism (Isomerism is the
phenomenon in which more than one compounds have the same molecular formula but different
molecular structures).
10. Rate of reaction: Organic compounds are generally less stable than inorganic compounds. Due
to covalent bonding in them, their reaction rates are often slow.
SLO: 11.1.2: Explain the diversity and magnitude of organic compounds.
1. Catenation: The ability of carbon atoms to link with other carbon atoms is called catenation.
The main reason for the existence of large number of organic compounds is that carbon atoms
can link with one another by means of covalent bonds to form long chain or rings of carbon
atoms. The chain can be straight or branched.
2. Isomerism: Another reason for the abundance of organic compounds is the phenomenon of
isomerism. Number of isomers increases with the increase in number of carbon atoms in the
given molecular formula.
3. Strength of covalent bonds of carbon: Due to its very small size, carbon can form very strong
covalent bonds with other carbon atoms, hydrogen, oxygen, nitrogen and halogens. This enables
it to form a large number of compounds.
4. Multiple bonding: In order to satisfy its tetravalency, carbon can make multiple bonds (i.e
double and triple bonds).
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SLO: 11.1.3: List some sources of organic compounds.
• Coal
Dead plants
• Natural gas
• Petroleum
• Carbohydrates
• Proteins
• Fats/oils
• Vitamins
Living organisms
• Medicine
• Cosmetics
Synthesis in
laboratory
• Paints
• Plastics,
• Fertilizer
• Detergents
• Synthetic fibres
• Rubber
• Insecticides and pesticides
SLO: 11.1.4: Recognizes the uses of organic compounds in daily life.
• Uses as food: The food we eat daily contain carbohydrates, fats, protein (energy sources),
vitamins and minerals which are required for healthy functioning of our body. • Uses as clothing:
Natural fibres (cotton, silk and wool etc.) and synthetic fibres (nylon, Dacron and acrylic etc.) are
used for clothing.
• Uses as houses: wood is cellulose. It is used for making houses and furniture. • Uses as fuel:
Coal, natural gas, petroleum etc are common fuels which we use for automobiles and domestic
purpose. Propane and butane which are gases obtained from natural gas are widely available as
LPG.
• Uses as medicines: A large number of organic compounds are used as medicine by us. Most of the
lifesaving medicines and drugs such as antibiotics are synthesized in laboratories. Compound of
phenol help to ensure antiseptic conditions in hospital operating rooms.
• Uses as raw material: To prepare a variety of material such as rubber, paper, ink, drugs, dyes,
paints, varnishes, pesticides. It is used in manufacturing of organic chemicals and products such
as plastic, acetic acid, antifreeze etc.
• Uses for welding and cutting metals: Acetylene is widely used in the oxy-acetylene form for
welding and cutting metals.
• Uses as solvent: Methanol is used as a solvent for fats, oils, paints and varnishes.
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SLO: 11.2.1: Classify organic compounds into Acyclic and cyclic compounds with
examples.
A. Acyclic / Open Chain Compounds / Aliphatic Compounds:
The carbon atoms are present in the form of an open chain. This chain may either be a straight
chain or a branched chain. Open chain compounds are those in which end carbon atoms are not
joined with each other.
• Straight
Chain Compounds: The carbon skeleton is in the form of a straight chain. Examples:
Propane CH3-CH2-CH3
Propene CH2=CH-CH3
• Branched
Chain Compounds: The carbon skeleton is in the form of a branched chain.
Examples: Isobutylene
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B. Cyclic or Closed Chain Compounds
They are marked by the presence of one or more closed chains or ring of atoms in their structure.
Depending on whether there is a presence of any other atom apart from carbon in the constitution
of the ring, they are further classified as:
a. Homocyclic or Carbocyclic Compounds
b. Heterocyclic Compounds
a. Homocyclic or Carbocyclic Compounds: The rings in these compounds are entirely made up
of carbon atoms. No other atom is present in the ring skeleton. These can be further divided
into two sub-classes:
I. Alicyclic Compounds
II. Aromatic Compounds
I. Alicyclic / Non-Benzenoid Compounds:
Carbocyclic compounds which do not have benzene ring in their molecules are called alicyclic
or non-benzenoid compounds. Their name is attributed to their resemblance to Aliphatic
compounds in their properties. The examples of this category include cyclopropane,
cyclobutane, cyclopentane, cyclohexane, etc.
II. Aromatic / Benzenoid Compounds:
These organic compounds contain at least one benzene ring in their molecule. A
benzene ring is made up of six carbon atoms with three alternating double bonds.
They are called aromatic because of aroma or smell they have.
These are cyclic unsaturated compounds. They derive their name from the Greek word Aroma
which means “fragrant smell” since most of these compounds bear a pleasant smell. These are
further classified into two types:
They are characterized by the presence of one or more fused or isolated benzene rings as well
as their derivatives in their structure. Depending upon the number of benzene rings that are
fused together in their structure, they can be further classified as Monocyclic, Bicyclic,
Tricyclic.
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b. Heterocyclic Compounds
When one or more heteroatoms such as oxygen, nitrogen, sulphur, boron, silicon etc. are present
in the ring such compounds are known as heterocyclic compounds.
• Alicyclic
heterocyclic compounds: Aliphatic heterocyclic compounds that contain one or
more heteroatoms in their rings are called alicyclic heterocyclic compounds.
• Aromatic
heterocyclic compounds Aromatic heterocyclic compounds that contain one or
more heteroatoms in their ring skeleton are called aromatic heterocyclic compounds.
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SLO: 11.2.2: Identify straight chain hydrocarbons up to ten carbon atoms on the basis of
their structural, condensed and molecular formulae.
General Formula of Alkanes: CnH2n+2
General Formula of Alkenes: CnH2n
General Formula of Alkynes: CnH2n-2
ALKANES (CnH2n+2)
Alkanes
Molecular Formula
Methane
CH4
Ethane
C2H6
Condensed formula
Structural formula
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ALKENES (CnH2n)
Alkenes
Molecular Formula
Condensed formula
Structural formula
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ALKYNES (CnH2n-2)
Alkynes
Molecular Formula
Condensed formula
Structural formula
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SLO: 11.3.1: List the name of straight chain alkanes up to decane.
SLO 11.3.2: Illustrate the formation of alkyl groups by the removal of hydrogen atom from
their corresponding alkanes (up to five carbon atoms).
Alkanes
Methane
CH4
Structural formula
Alkyl radical
Name
Methyl
Ethane
C2H6
Propane
Butane
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Pentane
SLO 11.4.1: Define the homologous series and its characteristics.
A homologous series is a family of organic compounds with the same functional group and
similar chemical properties.
Characteristics:
• All
members of a series can be represented by a general formula for example CnH2n+2 for
alkanes, CnH2n for alkenes and CnH2n-2 for alkynes.
• Successive members of the series differ by one unit CH2and 14 units in their relative
molecular mass.
• They have the same functional group.
• They have similar chemical properties.
• There is a gradual change in their physical properties as we go down the series from one
member to the next due to increase in their molecular masses.
• They can be prepared by similar general method.
SLO 11.4.2: Define the term isomerism and its types i.e. structural isomerism and
stereoisomerism.
Isomerism
Two or more compounds having the same molecular formula but different structural formulas
and properties are said to be isomers and the phenomenon is called isomerism.
Structural isomerism
Structural isomerism, or constitutional isomerism, is a type of isomerism where isomers have
same molecular formula but have different arrangements of atoms within the molecule. e.g. n
pentane, isopentane and neopentane are structural isomers.
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Stereoisomerism
When isomers have the same structural formula but differ in relative arrangement of atoms or
groups in space within the molecule, these are known as stereoisomers and the phenomenon as
stereoisomerism. The spatial arrangement of atoms or groups is also referred to as configuration
of the molecule and thus we can say that the stereoisomers have the same structural formula but
different configuration
SLO 11.4.3: Describe chain isomerism as a type of structural isomerism
Chain isomerism is a type of structural isomerism where the isomers have same molecular
formula but they differ in the order in which the carbon atoms are bonded to each other. Thus the
isomers arise with different types of branching in carbon chains. For example, Pentane, C5H12,
has three chain isomers. These are n-pentane, isopentane and neopentane.
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SLO 11.4.4: Draw possible structures of the chain isomers of given alkanes up to five
carbon atoms.
Isomers of pentane
SLO 11.5.1: Define the term functional group.
An atom or group of atoms or presence of double or triple bond which determine the
characteristic properties of an organic compound is known as the functional group.
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SLO 11.5.2: Classify various organic compounds i.e alkane, alkene, alkyne, alkylhalide,
alcohol, amine, ether, aldehyde, ketone, carboxylic acid, acid amide, ester and nitro
compounds on the basis of their functional groups.
c-x,
where
X=F,
Cl,
Br,
I
Alkyl
halides
/Haloalkanes
H3C-CH2-Cl
Chloroethane
Ethyl
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Draw and name simple molecules that contain the following functional group.
chloride
2,2-dimethyl propane
2-butyne
2-propanol
Methoxy ethane
Propanal
Butanone
Ethanoic acid
Ethyl Ethanoate
Bromoethane
Ethanamine
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SLO 11.5.3: Identify a molecule’s functional group using structural formula and systematic names
of compounds up to five carbon atoms.
SLO 11.5.4: Determine carboxylic acid, phenols, amines, aldehydes and ketones using different
tests.
Function
al
Group
Carboxy
lic acids
Phenols
Amines
Test
Observation
Inference / Result
Litmus Paper turns
into Red
Carboxylic acid
group is present
ii. NaHCO3 solution test:
Solution of Organic compound
in a test tube + add Sodium
bicarbonate
CO2 gas with
effervescence evolves
Carboxylic acid
group is present
iii. Ester formation test:
Take organic compound
solution in a test tube + add
small amount of alcohol + 1-2
drops of H2SO4
Fruity smell will
be given out
Carboxylic acid
group is present
Purple / Violet
coloration will appear
Phenol group is
present
Extremely
unpleasant odour
will be given out.
Amine group is present
i. Litmus test:
Dip Litmus Paper into
organic compound solution
i. Ferric Chloride Test:
Take organic compound solution
in a test tube + few drops of
freshly prepared FeCl3 Solution.
i. Carbyl amine test:
Heat organic compound in a
test tube + few mL of
Chloroform (CHCl3) + few
mL of alcoholic KOH
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Aldehydes
Ketones
i. Fehling’s solution test:
Take organic compound in a test
tube + Fehling’s solution A and B
+ boil it for 5 minutes.
Red precipitate will
be formed.
Aldehyde group is
present
ii. Tollens’ Test / Silver
Mirror Test:
Organic compound solution
+ Tollen’s reagent
(Alkaline
ammoniacal silver nitrate) +
reflex/ boil for few minutes
Silver Mirror formed
at the walls of the
test tube
Aldehyde group is
present
i. Phenyl hydrazine test:
Take organic compound +
phenyl hydrazine solution
Orange red
precipitate will be
formed
Ketone group is
present
ii. Sodium nitroprusside test:
sodium nitroprusside solution +
2-3 drops of NaOH solution +
pinch of organic compound
Red colour will be
formed
Ketone group is
present
i. Carboxylic Acid
Litmus paper:
• Shake a pinch of the given compound with water and add a drop of blue litmus solution. •
Solution will turn red.
NaHCO3
about 2.0cm3of 5% NaHCO3 solution and add a pinch of given compound. •
CO2 gas with effervescence evolves.
ii. Phenol:
• Take
Ferric chloride test:
• Add few crystals of organic compound to ethanol and water mixture then add few drops of
freshly prepared FeCl3 solution OR Add small amount of organic compound in a test tube and
add freshly prepared FeCl3solution.
• Purple or blue black colour appears.
iii. Amine
Sodium Hydroxide test:
• A little of the substance is boiled with dil NaOH.
• Ammonia gas is evolved.
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Carbyl amine test.
• Heat about 0.2g of the given compound and add 0.5 cm3of chloroform and 2-3 cm3of alcoholic
KOH.
• Extremely unpleasant odor will be given out.
iv. Aldehyde
Fehling’s solution
• Mix 3cm3of Fehling’s solution A with 3 cm3of Fehling’s solution B in a test tube.
Dissolve a few crystals of glucose in 3 cm3 water. Mix the two solutions. Heat the test
tube containing the above mixture for about five minutes.
• Red precipitate will be formed.
Sodium Bisulphite test
• Shake 0.2 gm or 0.5cm3of the given compound with 1-2 cm3of saturated solution of
sodium bisulphite.
• A crystalline white precipitate will be formed.
v. Ketone
Phenyl hydrazine test
• Shake a pinch of the given organic compound with about 2.0cm3of phenyl hydrazine
solution
• Orange red precipitate will be formed.
Sodium nitroprusside test
• Take about 2.0cm3of sodium nitroprusside solution in a test tube and add 2-3 drops of
NaOH solution. Now add a pinch of the given compound and shake.
• Red colour will be formed.
Tollen https://www.youtube.com/watch?v=7I-y3I3VzM8
Fehling https://www.youtube.com/watch?v=_C1llXoimns
Pheny hydrazine https://www.youtube.com/watch?v=JAQ060bSZG8
Phenol test https://www.youtube.com/watch?v=HSGlfbV7W84