Jee hydrocarbons ppt for cbse and ice....its about it jee main advanced

1. AROMATIC HYDROCARBONS
AROMATIC HYDROCARBONS

2. AROMATIC HYDROCARBONS

3. AROMATIC HYDROCARBONS
Greek word ‘aroma’ means
pleasant smelling. So,
Aromatic hydrogen carbons
are also called ‘arenes’.

4. AROMATIC HYDROCARBONS
AROMATIC HYDROCARBONS
 Benzene and compounds that resemble
benzene in their chemical behaviour are
called as aromatic compounds.
e.g.
 Benzene
 Naphthalene
 Anthracene
 Furan
 Thiophene O
:
:
S
:
:

5. AROMATIC HYDROCARBONS
 Benzene and compounds that resemble
benzene in their chemical behavior are
called as aromatic compounds.
AROMATIC HYDROCARBONS
e.g.
Caffeine ( )
Methyl salicylate
(PAIN RELIEVING OINTMENTS)

6. AROMATIC HYDROCARBONS
 In 1865, German chemist Friedrich August Kekule proposed the
structure of benzene.
Structure of Benzene

7. AROMATIC HYDROCARBONS
Structure of Benzene
 The structure of benzene consists of a cyclic structure with 3
conjugated double bonds which is systematically called
1,3,5-cyclohexatriene.
 All the carbons in benzene are sp2 hybridized.
H
H
H
H
H
H
H
H
H
H
H
H

8. AROMATIC HYDROCARBONS
where, n = 0,1,2,3,4…
Criteria for aromaticity
a) Cyclic
b) Planar (i.e., all atoms should be sp2 hybridized)
c) Completely Conjugated
d) Huckel’s Rule :
Compounds must contain (4n+2) π electrons

9. AROMATIC HYDROCARBONS
Benzene Pyrrole 1,3-Butadiene
Cyclobutadiene
Non Cyclic
Planar
Conjugated but
(4n + 2) π e– are not
present in 1-3
butadiene
Non Aromatic
Cyclic
Planar
Completely conjugated
(4n + 2 )π e– are not
present
Non Aromatic
Cyclic
Planar
Completely conjugated
(4n + 2 )π e–
n = 1
4(1) + 2 = 6 πe–
Aromatic
Cyclic
Planar
Completely conjugated
(4n + 2) π e–
n = 1
(4(1) + 2) πe– = 6 πe–
Aromatic
N
:
H

10. AROMATIC HYDROCARBONS
1. Which of the following is aromatic?
a)

b)
c)

d)

11. AROMATIC HYDROCARBONS
2. Which of the following is referred to as Huckel’s rule?
a) (4n+1)  electrons
b) (4n + 4)  electrons
c) (4n + 2)  electrons
d) None of the above

12. AROMATIC HYDROCARBONS

13. AROMATIC HYDROCARBONS
Benzenoids
 The compounds contain one or more benzene rings in their structure.
e.g.
Benzene Benzaldehyde
CHO
CLASSIFICATION OF AROMATIC COMPOUNDS

14. AROMATIC HYDROCARBONS
Benzenoids
CLASSIFICATION OF AROMATIC COMPOUND
Non-Benzenoids
 These compounds do not contain any benzene ring in their structure.
Furan
O
:
:
Thiophene
S
:
:
Pyridine
:
N
e.g.

15. AROMATIC HYDROCARBONS
Aromatic compound Aliphatic compound
Contains higher %
of carbon.
1. Contain lower % of
carbon.
1.
2. Burns with sooty
flame.
Burns with non-sooty
flame.
2.
Cyclic compound
with alternate single
and double bonds.
3. Open chain
compounds.
3.
Distinguish Between Aromatic and Aliphatic compounds
prefers substitution
reactions.
4. Alkanes
(Subsitution reactions)
Alkens & Alkynes
(addition reactions)
4.
% of carbon in Benzene
Total mass of C in C6H6
Total mass of C6H6
 100
=
12  6
12  6 + 6  1
 100
72
78
=  100
0.9230  100
=
= 92.30 %
=
% of carbon in Hexane
Total mass of C in C6H14
Total mass of C6H14
 100
=
12  6
12  6 + 14  1
 100
72
86
=  100
0.8372  100
=
= 83.72 %
=

16. AROMATIC HYDROCARBONS
1. Aromatic Compounds burn with
a) Sooty Flame
b) Non - Sooty Flame
c) Both a & b
d) None of these

17. AROMATIC HYDROCARBONS
2. Naphthalene belongs to which type of aromatic compound?
a) Benzenoid
b) Non- Benzenoid
c) Anti-aromatic
d) All the above

18. AROMATIC HYDROCARBONS
3. All the carbon atoms in benzene are…
a) sp3 Hybridised
b) sp2 Hybridised
c) sp Hybridised
d) sp3d Hybridised

19. AROMATIC HYDROCARBONS
4. Benzene contains…
a) 8 electrons
b) 10 electrons
c) 6 electrons
d) 2 electrons

20. AROMATIC HYDROCARBONS

21. AROMATIC HYDROCARBONS
Monosubstituted benzene can be named by placing the name
of substituent as prefix to benzene.
A) MONOSUBSTITUTED BENZENE
Rule 1 :
H NO2 Br
 Benzene  Parent compound
 Substituent  Prefix to Benzene
Chlorobenzene Nitrobenzene Bromobenzene
Cl H H
NOMENCLATURE OF AROMATIC COMPOUNDS
Benzene,in which only
one H-atom is replaced
by alkyl /functional
group

22. AROMATIC HYDROCARBONS
Rule 2 : The name of benzene derivatives are known by common names
which are accepted by IUPAC.
Phenol
OH CH3
Toluene
NH2
Aniline Benzoic acid
COOH
H H H H

23. AROMATIC HYDROCARBONS
If alkyl substituent is larger than benzene, then benzene
becomes substituent and prefixed as (Phenyl).
Rule 3 :
Phenyl
(C6H5 –)
Alkyl group
contains more
than 6 carbons
Linked to
functional
group
Benzene
Benzyl
C6H5 – CH2 –

24. AROMATIC HYDROCARBONS
–3–phenyl
CH3 – CH – CH2 – CH2 – NO2
e.g.
2–Phenyl
CH3 – CH – CH2 – CH2 – CH2 – CH2 – CH3
Parent chain of
carbon
i.e., Heptane
Substituent
i.e., phenyl
2 4 5 6
3 7
1
Heptane
Parent chain
of carbon
i.e., butane
2
3 1
butane
1–Nitro
4

25. AROMATIC HYDROCARBONS
alcohol
OH Functional
group (alcohol)
CH2 – CH2 – CH2 – Cl
Parent chain of
carbon
i.e., Propane
CH2 –
Benzyl
–3–phenyl
2
3 1
Propane.
1–chloro
e.g.

26. AROMATIC HYDROCARBONS
a) 2-Phenyl 4-nitro butane b) 1-nitro 3-phenyl butane
c) 3-methyl 3-phenyl 1-nitro propane d) All the above
1. The IUPAC name of the following compound
CH3 – CH – CH2 – CH2 – NO2

27. AROMATIC HYDROCARBONS
a) 1-nitro 3-benzene carbaldehyde b) 3-nitro benzene carbaldehyde
c) 3-formyl nitro benzene d) All the above
2. The IUPAC name of the following compound
CHO
NO2

28. AROMATIC HYDROCARBONS

29. AROMATIC HYDROCARBONS
e.g.
Position (1, 4) – para (p –)
Functional Group
1
2 Position (1, 2) – ortho (o –)
Position (1, 3) – meta (m –)
3
4
B) DISUBSTITUTED BENZENE
NOMENCLATURE OF AROMATIC COMPOUNDS
Benzene in which only
two H-atoms are replaced
by alkyl /functional
groups
ISOMERS OF DISUBSTITUTED BENZENE

30. AROMATIC HYDROCARBONS
For same substituents, di will be used as prefix.
NO2
NO2
Cl
Cl
o- dichloro benzene
(1, 2 – dichloro benzene) (1, 3 – dinitro benzene)
1
2
1
3
m- dinitro benzene
Rule 1 :

31. AROMATIC HYDROCARBONS
For different substituents, they can be numbered and entered in
alphabetical order.
I
Br
p-Bromoiodobenzene
(1-Bromo-4- Iodobenzene)
Rule 2 :
1
2
3
4
Incorrect
way of
numbering
1
2
3
4
correct way
of numbering
m-chloro nitrobenzene
(1-Chloro-3- Nitrobenzene)
Cl
NO2
1
2
3
correct way
of numbering
1
2
3
Incorrect
way of
numbering

32. AROMATIC HYDROCARBONS
If one of the two groups is given special name to the molecule,
the compound is named as the derivative of the special
compound.
NH2
Cl
o-Chloro aniline
1 2
(2-Chloroaniline)
Rule 3 :

33. AROMATIC HYDROCARBONS
CH3
NO2
m-Nitro toluene
Rule 3 :
1
2
3
(3-Nitrotoluene)
If one of the two groups is given special name to the molecule,
the compound is named as the derivative of the special
compound.
OH
Br
p-Bromo phenol
(4-Bromo phenol)
1
2
3
4

34. AROMATIC HYDROCARBONS
If one of the groups, which gives a special name to the
compound is present, the special group is considered in
position 1.
Rule 4 :
NO2
OH
Cl
CH3
C2H5
NH2
1+2+ 3 6
=
1+5+ 6 12
=
2
3
4
1
2
3
4
5
6
5
1
6
(3–Ethyl–2–methyl aniline)
1+2+4 7
=
1+4+6 11
=
2
3
5
6
4
1
1
2
3
4
5
6
(2–Chloro–4–nitro phenol)
Lowest combination Lowest combination
Highest combination
It follows lowest
sum rule

35. AROMATIC HYDROCARBONS
If more than two groups are attached to the direction of
numbering, it should be such that it gives lowest combination
of numbers.
Rule 5:
Br
Br
Br
1, 2, 4-Tribromobenzene
1
2
3
4
1+2+4 7
=
Lowest combination
1
2
3
4
5
6
1+4+6 11
=
Highest combination
Br
CH3
CH3
1
2
3
4
1+2+4 7
=
Lowest combination
1
2
3
4
5 6
1+4+6 11
=
Highest combination
4–Bromo–1, 2–dimethyl benzene
5
6
5
6

36. AROMATIC HYDROCARBONS
1. Which of the following is 2, 4, 6-Trinitrotoluene?
CH3
NO2
O2N
NO2
a)
CH3
NO2
NO2
NO2
b)
CH3
NO2
O2N
NO2
c)
CH3
NO2
NO2
d)

37. AROMATIC HYDROCARBONS
2. The structure of Aniline is…
b)
c) d)
a)
OH NH2
OCH3 CHO

38. AROMATIC HYDROCARBONS
3. The correct structure of m-dinitro benzene is…
b)
c) d)
a)
None of these
NO2
NO2
NO2
NO2
NO2
NO2

39. AROMATIC HYDROCARBONS
4. Name of the compound is…
COOH
b)
c) d)
a)
b and c
Acetophenone Benzaldehyde
Benzoic acid

40. AROMATIC HYDROCARBONS
Thank you…