Useful for students of Standard/ Class/ Grade 10th of SSC, CBSE; 8th ICSE

1. Standard/ Class/ Grade - 10 SSC, CBSE; - 8 ICSE
Carbon Compounds
Gurudatta K Wagh

2. Standard 10 Chapter 9 Carbon Compounds
Contents
Hydrocarbons
Saturated and unsaturated
Catenation
Straight chain and branched chain
Functional groups
Homologous series
Nomenclature
Chemical properties
Reactions
Soaps and detergents

3. Standard 10 Chapter 9 Carbon Compounds
Organic compounds
Compounds directly or indirectly obtained from plants
and animals
Organic chemistry is also known as the chemistry of
carbon compounds
Inorganic compounds
Compounds obtained from minerals

4. Urea CO(NH2)2 , an organic
compound, was synthesized from
an inorganic compound
ammonium cyanate NH4(NCO)
by Friedrich Wohler, a German
chemist

5. Hydrocarbons
Hydrocarbons (Parent compounds/ fundamental
organic compounds)
All organic compounds contain hydrogen along with
carbon
Some organic compounds also contain oxygen,
halogens, and sometimes nitrogen and sulphur

6. Methane (marsh gas) CH4
In methane C is bonded to four H atoms
Electronic configuration - C (2, 4),
H 1
C has four electrons in its
outermost orbit – tetravalent
If C gets four electrons in the
second orbit, its outermost orbit
will be completely filled and will
make it stable to attain the
nearest inert gas configuration
[Neon (2, 8)]

7. Covalent bond in methane
• C gets four electrons by sharing one electron with
each H atom
• C-H bonds are formed. C atom is centrally placed
• Bonds formed by sharing of electrons are known
as covalent bonds
• A single covalent bond is formed by sharing of two
electrons
Structure

8. Electron dot and cross structure
If the electrons of C are shown as "x" and the
electrons of H as ". ", then methane appears as
methane

9. Properties of organic compounds with covalent
bonds
(1) Low melting point and boiling point
(2) Generally insoluble in water but are soluble in
other organic solvents
(3) Poor conductors of heat and electricity

10. Covalent bond in oxygen
The atomic number of
oxygen is 8
Six electrons are present in
its outermost shell
It requires 2 more electrons
to complete its octet

11. Each oxygen atom shares its valence electron with the
valence electron of another oxygen atom to give two
shared pairs of electrons which results in the
formation of O2 molecule
If two electron pairs are shared between two atoms,
then a double covalent bond (=) is formed
Structure
O::O or O = O or O2

12. Saturated and unsaturated hydrocarbons
Saturated hydrocarbons Carbon atoms are linked
to each other only by single bonds
Unsaturated hydrocarbons Hydrocarbons in which
carbon atoms are linked to each other by double or
triple bonds are known as unsaturated hydrocarbons

13. Name Bond
Alkanes Single C-C bonds
Alkenes Double C=C bonds
Alkynes Triple C≡C

14. Saturated and unsaturated hydrocarbons can form
straight chains or closed chain structures
These chains can have branches and cross links and
are known as closed chain or ring compounds

15. Catenation The remarkable property of carbon atom
to form bonds with itself and give rise to a single
large structure or chain
Definition: The property of direct bonding between
atoms of same element to form a chain
The carbon chains can be straight or branched
forming large molecules

16. Allotropes of Carbon
Allotropy
The phenomenon of existence of a substance in
various physical forms but same chemical form

17. Diamond and graphite
Both are formed by carbon atoms
Diamond Graphite
hard, beautiful, crystalline soft, grayish black,
crystalline
Each carbon atom is
linked to four other
neighbouring, carbon
atoms held at the corners
of a regular tetrahedron by
covalent bonds to form a
rigid three dimensional
structure
Each carbon atom is
attached to three other
carbon atoms forming a
hexagonal planar
structure

18. Physical properties of graphite and diamond are
different but their chemical properties are the same
Diamond Graphite
There are no mobile
electrons in the system
and hence diamond
crystal is a non-conductor
of electricity
Free electrons move
throughout the entire
layers, and hence
graphite is a good
conductor of electricity
Used as precious stone in
jewellery.
Black diamonds are used
for cutting glass
Used in making
electrodes and carbon,
lubricants and lead
pencils

19. Parent hydrocarbons
Methane CH4 is a saturated hydrocarbon and an
alkane
If we increase the number of carbon atoms by 1 and
the number of hydrogen atoms by 2, then we get
ethane C2H6 and is the next member in the family of
alkanes
If we add one more carbon atom and two more
hydrogen atoms to ethane, we get propane C3H8
The general formula for alkanes is CnH2n+2 where n is
the number of carbon atoms

20. Isomers and isomerism
Compounds with identical molecular formula but
different structure hence called isomers and the
property is known as isomerism
Straight chain and branched chain
Pentane C5H12
Three possible carbon skeletons
The carbon atoms are linked together in the form of
open chain
These compounds also contain branched chain

21. Pentane C5H12
Three possible carbon skeletons

22. Pentane C5H12

23. Closed ring
Cyclohexane C6H12
The two ends of a chain of carbon atoms are joined
together

24. Structure of Benzene C6H6 Benzene ring is made
up of six carbon atoms, in which each carbon atom is
joined by a single bond on one side and double bond
on other side (alternate single bond and double
bonds)

25. Functional groups in organic compounds
All organic compounds are considered as the
derivatives of hydrocarbons
The derivatives are formed by replacing one or more
hydrogen atoms in a molecule of hydrocarbon by
some other atom or group of atoms
After replacement, a new set of compounds is formed
which has functions (properties) different from the
parent hydrocarbon

26. Functional group
It is the atom or group of atoms present in the
molecule which determines characteristics property
of organic compounds
If one hydrogen in methane CH4 is replaced by an
-OH group, then a compound known as methyl
alcohol CH3OH is formed
The -OH group is known as the alcoholic functional
group

27. Type General formula
R = CnH2n+1
R = alkyl group
Functional
group
Compound containing functional
group
Name Formula
Alcohols R-OH -OH Ethyl alcohol C2H5OH
Aldehydes R-CHO 1) Acetaldehyde 2)
Ketones 3) 4) Acetone
(Dimethyl ketone)
5)
Carboxylic acid R-COOH -COOH Acetic acid CH3COOH
1) aldehyde 2) acetaldehyde 3) ketone 4) carbonyl group
5) acetone

28. 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
Some important characteristics of homologous
series
(1)The general formula of all compounds in the series
is the same
(2) They have the same functional group

29. (3) Physical properties like melting point, boiling point,
density, generally show a gradual change with increase of
molecular formula in the series. On the other hand,
chemical properties of the member show close
resemblance because of the presence of the same
functional group in them
(4) Consecutive members of the series differ from one
another by -CH2- group which is known as the methylene
group and their molecular weight differs by 14 units

30. 1. Alkanes The Alkane family is a homologous series
and characterized by the general formula CnH2n+2
Methane CH4
Ethane C2H6
Differ by –CH2 units
Ethane C2H6
Propane C3H8
Differ by –CH2 units
Butane C4H10
Pentane C5H12
Differ by –CH2 units
2. Alcohols CnH2n+1OH
Methyl alcohol CH3OH
Ethyl alcohol C2H5OH
Differ by –CH2 units
Propyl alcohol C3H7OH
Butyl alcohol C4H9OH
Differ by –CH2 units

31. Nomenclature of organic compounds
IUPAC (lnternational Union of Pure and Applied Chemists)
system is the latest and widely accepted system for giving
systematic names to organic compounds
All organic compounds are considered as derivatives of
saturated hydrocarbons and are known as Alkanes
To express the name of the compound the basic carbon chain
is modified by 'root'. A root indicates the “nature of basic carbon
skeleton”, prefix indicates “phrase before” and suffix indicates
“phrase after”

32. Terminology used in nomenclature
Root: It indicates the nature and the number of
carbon atoms in the basic carbon skeleton
Bond with Root word
One C atom Meth-
Two C atom Eth-
Three C atom Prop-
Four C atom But-
Five C atom Pent-
Six C atom Hex-
Seven C atom Hept-
Eight C atom Oct-

33. Suffix: It denotes the type of bonds or functional group
present in the carbon chain. A Suffix is added to a
root word to indicate the saturation or unsaturation in
the carbon chain
C chain Suffix Root name
Saturated –C–C- -ane Alkane
Unsaturated
–C=C-
-ene Alkene
Unsaturated
-C≡C-
-yne Alkyne

34. Prefix: It indicates the presence of other functional
groups and their position
Examples
Ethanol C2H5OH
One hydrogen atom is substituted by the -OH group

35. Select the longest chain of carbon atoms
The name of the parent alkane is ethane
Since the functional group is alcohol, remove the ‘e’
from the word ethane and substitute it with ‘ol’ ('ol'
stands for alcohol)
The carbon atom to which the -OH group is attached
is numbered as C1 and the other carbon atoms are
numbered accordingly
The compound C2H5OH is named as ethan-1-ol
indicating that the functional group-OH is attached to
the carbon atom at the end of the chain

36. 2-bromopropane 1-bromopropane
• One hydrogen atom in the chain is substituted by
-Br group
• The longest chain is of three carbon atoms
• The name of the parent alkane is propane
• The functional group is halide (in this case bromo)
• The carbon atom nearest to the substituted group is
numbered as C1 and C2, respectively
• The compounds are called 2-bromopropane
and 1-bromopropane, respectively

37. Unsaturated compound containing a double bond
CH2=CH2
CH2=CH-CH3
CH2=CH-CH2-CH3
CH3-CH=CH-CH3
Ethene (ethylene)
Propene
Butene-1
Butene-2

38. CH3CH2CH=CH2
4 3 2 1
 The longest chain of carbon atoms is four
 The parent alkane is butane. The above chain is
named as butene
 In the structure, the numbering of carbon atoms starts
from the carbon atom nearest to the double bond. In
the above case, the carbon atom on the extreme right
is numbered 1
 The position of the double bond in the chain is
indicated by prefix the lower number of the carbon
atoms between the double bonds. In the above case,
since the double bond is between C1 and C2, the
compound is known as but-1-ene

39. Unsaturated compound containing a triple bond
H-C≡C-H ethyne/ acetylene
The same rules as for double bonds are followed. The
suffix is changed from -ene- to -yne-

40. Chemical properties of carbon compounds
Combustion All hydrocarbons burn in air or oxygen
to form CO2 and H20
The reactions are exothermic with the evolution of a
large amount of heat
(1) CH4(g) + 2O2(g) → CO2(g) + 2H2O (g) + Heat and light
(2) 2C4H10(g) + 13O2(g) exothermic 8CO2(g) + 10H2O(l) + 2658 KJ Heat
combustion

41. If very limited air is supplied, then methane gives carbon
black
CH4 + O2 → C + 2H20
limited air → carbon black
Saturated hydrocarbons give a clean flame (oxidizing
flame) but when unsaturated carbon compounds burn,
they give a yellow flame (reducing flame) with lots of
black carbon
When gas or kerosene stove is used a sufficient quantity
of air is used and hence we get clean blue flame

42. Addition Reaction
The reaction in which two molecules react to form a
single product is known as addition reaction. This type
of reaction occurs only in unsaturated compounds
where there are double or triple bonds.
(a) Reactant adds to the carbon atoms of C=C double
and C≡C triple bond
ethene + bromine → ethylene dibromide

43. (b) Addition of hydrogen molecule to ethene gives
corresponding ethane i.e. saturated product
(unsaturated compound gets converted into saturated
compound)

44. Substitution Reaction
Reactions where substitution of one (or more atoms)
in a molecule for another atom takes place are called
substitution reactions
CH4 + Cl2 UV rays CH3Cl + HCl (H substituted by Cl)
CH3CH2I + KOH → CH3CH20H + KI (I substituted by OH)

45. Some important carbon compounds
Ethanol
Ethanol C2H5OH is called ethyl alcohol or spirit, has a
linear structure CH3CH2OH. It is a colourless liquid
and has a pleasant odour. Boiling point is 78 °C and
freezing point is -114 °C. It is combustible and burns
with blue flame

46. Reactions with ethyl alcohol
(a) When sodium comes in contact with ethyl alcohol it
gives hydrogen gas
2C2H5OH + 2Na → 2C2H5ONa + H2
(ethyl alcohol + sodium → sodium ethoxide + gas)
(b) When ethyl alcohol reacts with PCI3 it forms ethyl
chloride
3C2H5OH + PCI3 → 3C2H5Cl + H3PO3
(ethyl alcohol + phosphorous trichloride → ethyl
chloride + phosphorous acid)

47. Reactions with ethanoic acid (acetic acid) C2H4O2
Has a linear structure CH3COOH, is a weak acid,
colourless, corrosive liquid and has pungent smell at
ordinary temperature. Below 290 K it solidifies to an
ice like mass called glacial acetic acid

48. (a) Reaction with halogens
When acetic acid reacts with chlorine gives
monochloroacetic acid
CH3COOH + Cl2 → CH2CICOOH + HCI
Monochloroacetic acid
CH2CICOOH + Cl2 → CHCI2COOH + HCI
Dichloroacetic acid
CHCI2COOH + Cl2 → CCl3COOH + HCI
Trichloroacetic acid

49. (b) Reaction with metals
When acetic acid reacts with Na or Zn it gives sodium
acetate with liberation of Hydrogen gas
2CH3COOH + 2Na → 2CH3COONa + H2
(c) Reaction with alcohol
When acetic acid reacts with ethyl alcohol in
presence of anhydrous ZnCl2, ethyl acetate is formed
CH3COOH + C2H5OH → CH3COOC2H5 + H2O

50. Soaps and Detergents
• Soaps are cleansing agents which are capable of
reacting with water to dislodge the unwanted
particles from cloth or skin
• The molecules of soap are sodium or potassium
salts of long chain carboxylic acids
• A soap molecule has a tadpole shaped structure
• At one end (long non polar end) of soap molecule
is a hydrocarbon chain i.e. insoluble in water but
soluble in oil

51. • At the other end (short polar end) of soap
molecule there is a carboxylate ion which is
hydrophilic i.e. water soluble but insoluble in oil
• When soap is mixed with water, the solution
becomes concentrated and causes foaming
• The long non-polar end of soap gravitates
towards and surrounds the dirt and absorbs the
dust in it
• The short polar end with the carboxylate ion turns
the water away from the dirt
• The soap molecule thus helps in dissolving the
dirt in water and we can wash our clothes clean

52. Toilet soap Laundry soap
High quality of fats used
for raw material
Cheaper quality of oils
and fats are used
Expensive perfumes
added
Cheaper perfumes
added
No free alkali content
present to prevent
injuries to skin
Free alkali present for
cleaning action

53. THANK YOU
SSC Std 10th Textbook
CBSE Std 10th Textbook
YouTube
Google
Wikipedia
Suggestions and Appreciations welcome
gkwagh@gmail.com