Review
1.
2.
3.
3-ethyl,6-methyl nonane
2, 7, 8-Trimethyldecane
2, 3 Dimethylhexane
cpomunsod
compounds
nadidtoi necariotn
Addition Reaction
NSUBOITUTI TBONICTAER
Subtitution Reaction
BENZENE
QUARTER 1- WEEK 7
Definition of Terms

Addition reaction- two or more molecules combine to form a larger
one.

Aromaticity- cyclic conjugated organic compounds such as benzene,
that exhibit special stability due to resonance delocalization of πelectrons.

Aromatic compounds- Any substances whose molecules have benzene
rings and whose rings give substitution reactions instead of addition
reactions.

Conjugation- series of overlapping p-orbitals.

Derivative- is a compound that is derived from a similar compound by a
chemical reaction.

Substitution reaction- is a chemical reaction during which one
functional group in a chemical compound is replaced by another
functional group.
BENZENE
Benzene
or benzol, which was first
identified by Michael Faraday in 1825,
is an organic chemical compound with
a molecular formula C6H6.
BENZENE
It
is the typical example of
an aromatic compound. It is
a colorless, carcinogenic,
flammable liquid with a
characteristic odor.
BENZENE
A
benzene ring is relatively stable
because of π-electron
delocalization. Benzene and
many other aromatic
hydrocarbons are obtained from
petroleum and coal tar.
REACTIONS OF BENZENE

Most of the reactions that benzene undergoes
are substitution reactions in which the hydrogen
atoms on the ring are replaced by other atoms
or groups. For example, the usual reaction of
benzene with bromine is a substitution reaction
(not an addition reaction).
NOMENCLATURE OF BENZENE
1.
-
Monosubttituted
When one of the positions on the ring has been substituted
with another atom or group of atoms, the substituent is
indicated by a prefix to the word benzene.
Give the Common Name of the Following Example
Xylene
Toluene
Phenol
Give the Molecular Formula of the Following Example
C6H5CH2CH3
C6H5CH3
C6H5OH
NOMENCLATURE OF BENZENE
Disubtituted
- When two or more groups are attached to the
benzene ring, both what they are and where they
are must be specified.
2.
Ortho,
Meta, and Para are terms for 1,2, 1,3-, and 1,4 relationships that are
used in naming disubstituted benzenes.
Try This!
m – dinitrobenzene
Or 1, 3- dinitrobenzene
o- dichlorobenzene
Or 1, 2- dichlorobenzene
Ortho-bromochlorobenzene
Para-bromrnitrobenzene
NOMENCLATURE OF BENZENE

A disubstituted benzene is usually named as a derivative not of
benzene but of a monosubstituted benzene when the latter
has a common name, like toluene or aniline. Then the o-, m-, or
p- designations are used to specify relative positions of the two
groups. For example.
Another Example
m-Nitrotoluone
m-Chlorophenol
NOMENCLATURE OF BENZENE
4. Trisubtituted
-We cannot use the ortho, meta, or para designations with
sufficient precision to make an ambiguous name. We
must now use numbers assigned to ring positions in such
a way as to use the lowest numbers possible.
Examples
3-Iodo-5-nitrophenol
NOMENCLATURE OF BENZENE
4. Phenyl Group
-When the benzene ring is a substituent of a parent
chain. The benzene ring is regarded as a
substituent when the parent chain has greater
than six carbons.
Another Example
1-Phenyloctane
1-methylbutylbenzene
Let’s Review!
1. What
are the 3 prefixes we used
when naming disubtituted
benzene?
Answer: ortho, meta, and para
2. Distinguish if the given example
is monosubtituted, disubtituted and
trisubtituted benzene.
monosubtituted
Disubtituted
Application

Do you know that Benzene is used in various industrial processes such as in the
manufacture of;
Lubricants
Plastics and Rubbers
Medicines
Evaluation

What is the name of the given compound?
a) Nitrogenbenzene
b) Nitrobenzene
c) Nitrooxygenbenzene
d) Nitricbenzene
B.

What prefixes are used in naming a 1, 3
disubstituted benzene?
a)
Ortho
b)
Meta
c)
Para
d)
Tri
B

It is the typical example of an aromatic
compound. It is a colorless, carcinogenic,
flammable liquid with a characteristic odor.
a)
Benzene
b)
Benzine
c) Phenyl
d) Phenol
A
What is the molecular formula of Iodobenzene?
a) C6H5I
b) C6H6I
c) C6H5Io
d) C6H6Io
A
When the benzene ring is a substituent of a parent
chain, it is referred to what group?
a) Benzene group
b) Ethyl group
c) Phenyl group
d) Phenol group
C
 How will you name a bromine attached to 1, 4 benzene
group?
a) 1, 4 p - bromobenzene
b) 1, 4 m- bromobenzene
c) 1, 4 o- bromobenzene
d) 1, 4 b- bromobenzene
A
 Which of the following is NOT considered as one of the
use of benzene?
a) It is used in degreasing of metal.
b) It is used for manufacturing of nylon fibers.
c)
It is used in the preparation of benzyl.
d)
It is used in the manufacture of other chemicals
C
Which of the following example is NOT a property
of benzene?
a)
It is immiscible in water but soluble in organic solvents.
b)
It is a colourless liquid and has an aromatic odor.
c)
It has a density of 0.87g cm-3. It is lighter than water.
d)
It is not highly inflammable and burns with a sooty
flame.
C
 What
is the name of the given example?
a)1, 4 dichlorobenzene
b)1, 4 p- dichlorobenzene
c)1, 4 m- dichlorobenzene
d)1, 4 o- dichlorobenzene
C
 What
is the general formula of benzene?
a)
CnH2n-6
b)
CnH2n
c)
CnH2n-2
d)
CnH2n+2
A
Preservation
Assignment
 For
your assignment, give at least 5
examples of chemicals used in
preserving foods.