ACKNOWLEGMENT

I Would Like To Express my special thanks

of Gratitude to my teacher Mr. Devendra
kumar sen Who gave the golden opportunity
to do this wonderful activity on topic
{haloalkane and haloarenes }
Which also helped me to know about so many
things and ,
I’m really thankful to them .
 Certificate

This is to certify that Piyush patel of class XII

(PCM) has successfully completed his
chemistry activity on topic { haloalkane and
haloarenes } as prescribed by Mr. Devendra
kumar sen during the academic year 2022-
2023 as per the guideline given by teacher .

Subject teacher signature

Principal teacher signature
Haloalkanes and Haloarenes

Haloalkanes and haloarenes are the

hydrocarbons in which one or more
hydrogen atoms have been replaced
with halogen atoms. The primary
difference between haloalkanes and
haloarenes is that haloalkanes are
derived from open-chain hydrocarbons
(alkanes) whereas haloarenes are
derived from aromatic hydrocarbons

Table of Content :

 Overview of Haloalkanes and

Haloarenes
 Related Topic of Haloalkanes
and Haloarenes

 Classification of Haloalkanes
and Haloarenes

 Uses of Haloalkanes and

Haloarenes
Overview of Haloalkanes and Haloarenes :

Haloalkanes are commonly referred to as alkyl

halides whereas haloarenes are commonly
referred to as aryl halides. These compounds
can contain multiple halogen atoms, as
illustrated below.
Generally, In haloalkanes, the halogen
atoms are attached
to sp3 hybridized carbon atoms whereas
in haloarenes, the point of attachment is
sp2 hybridized carbon atom. The
difference in the hybridization state of
the carbon atom in C-X bond is
responsible for the different
characteristics which the two families
have. The presence of halogens makes
haloalkanes and haloarenes more
chemically reactive than the parent
alkanes and aromatic compounds.
These compounds have many medicinal
uses as well.
Classification of Haloalkanes and
Haloarenes :
Alkyl halides and aryl halides can be
classified based on the following
parameters:
1. Number of halogen atoms in
the molecule
2. sp3  hybridized carbon-
halogen bond.
3. sp2  hybridized carbon-
halogen bond.
The classification of haloalkanes
and haloarenes is described in the
tabular column provided below.
 Monohaloalkanes and
Contain 1 halogen atom
Monohaloarenes

Classification based on the

number of halogen atoms. Dihaloalkanes and Dihaloarenes 2 halogen atoms are attached

Trihaloalkanes and Trihaloarenes Contain 3 halogen atoms

Halogen is attached to an alkyl

Alkyl Halide
chain.

The halogen atom is attached to

Haloalkanes and haloarenes in an sp3 hybridized carbon which is
Allylic Halide
which the halogen is attached to adjacent to C=C (double bond or
an sp3 hybridized carbon. sp2 hybridized carbon)

The halogen is attached to an

Benzylic Halide sp3 hybridized carbon which is
attached to a benzene ring.

The halogen atom is attached to

Vinyl Halide
C=C (sp2 hybridized carbon).
Compounds in which the
halogen is attached to a
sp2 hybridized carbon The halogen is attached to a
Aryl Halide sp2 hybridized carbon which
belongs to an aromatic ring.
Nomenclature of Haloalkanes
Initially, there was no proper system for the naming of compounds. Mostly there were trivial names that
were used depending upon the country and region. These trivial names were based on the discoverer or the
nature of the compound or its place of discovery.
The system of trivial names was not standard and led to much confusion, thus raising the need for a
standard system for the naming of organic compounds. IUPAC came up with a set of rules that are used
universally for the naming of organic compounds.
There are two names associated with every compound:

1. Common name – It is different from a trivial name in the sense that it also follows a rule for its
nomenclature.
2. IUPAC name –  The IUPAC (International Union of Pure and Applied Chemistry) naming system
is the standard naming system that is generally used by chemists.

Table of Contents
 Rules of Nomenclature
 The Methodology of Writing Name
 Nomenclature of Haloalkanes
 Nomenclature of Haloarenes
 Recommended Videos
Rules of Nomenclature
1. Find the longest carbon chain.
2. Number the longest carbon chain such
that the carbon atom(s) to which the
halogen(s) is/are attached get the lowest
number(s).
3. Multiple halogen atoms are labelled
with the Greek numerical prefixes such as
di(for two halogen atoms), tri(for three
 halogen atoms), and tetra(for four halogen
atoms) to denote the number of identical
halogen atoms attached to a carbon atom.
If more than one halogen atom is attached
to the same carbon atom, then the numeral
is repeated for that much time.
4. In case, different types of halogens are
attached, they are named alphabetically.
5. The position of the halogen atom is
indicated by writing the position and name
of the halogen just before the name of the
parent hydrocarbon.
The Methodology of Writing Name
1. First, write the root word for the parent
hydrocarbon (depending upon the no. of
carbon atoms in the longest carbon chain).
2. Secondly, calculate the number of
halogen atoms present. If there are
multiple halogen atoms present, then
arrange the halogens alphabetically in the
prefix, labelling them with their respective
positions. But, if the same halogen atom is
present more than once then use the
prefixes di, tri, tetra, etc.
Nomenclature of Haloalkanes
Alkyl halides are named in two ways. In the
common system, the alkyl group is named first
followed by the appropriate word chloride,
bromide, etc. The common name of an alkyl
halide is always written as two separate words.
In the IUPAC system, alkyl halides are named
haloalkanes. The other rules followed in
naming compounds is that
 Select the longest chain of carbon atoms
containing the halogen atom.
 Number the chain to give the minimum
number to the carbon-carrying halogen
atom.
 If multiple bonds (double or triple bonds)
are present, then it is given the preference
in numbering the carbon chain.
 The IUPAC name of any halogen
derivative is always written as one word.
Compoun Common
IUPAC Name
d Name
CH3-Cl Methyl Chloromethane
 Chloride
CH3-CH2-
Ethyl bromide Bromoethane
Br
CH3- tert-Butyl 2-Bromo-2-
C(CH3)2-Br bromide methylpropane
CHCl3 Chloroform Trichloromethane
CH3- Ethylidene
1,1-Dibromoethane
CH(Br)2 bromide
CH2=CH-
Allyl iodide 3-Iodoprop-1-ene
CH2-I

Nomenclature of Haloarenes
 Aryl halides are named by prefixing
“halo” to the name of the parent aromatic
hydrocarbon.
 If there is more than one substituent on the
ring then the relative positions of the
substituents are indicated by mathematical
numerals.
 In the common system, the relative
position of two groups is shown by
prefixes ortho, meta or para.
The common and IUPAC names of some
representative haloarenes are given below.

IUPAC Names of Some Haloarenes

Haloarenes: Nature of C-X bond
Haloarenes are the chemical compounds
containing arenes, where one or more hydrogen
atoms bonded to an aromatic ring are replaced
with halogens. The nature of the C-X bond
depends on both the nature of carbon in the
aromatic ring and the halogen attached. Halogens
are generally denoted by “X”.
As we know halogens are group 17 elements
having high electronegativity namely, fluorine (F),
chlorine (Cl), bromine (Br), iodine (I) and astatine
(At). Out of them, fluorine has the highest
electronegativity. The elements in this group are
just one electron short of completing their nearest
noble gas configuration.
Carbon in haloarenes is a 14th group element with
comparatively lesser electronegativity in
comparison to halogen molecules. This is due to
the fact that electronegativity increases across a
period from left to right.
Salient Points on the Nature of C-X Bond in
Haloarenes
 The C-X bond in haloarenes is polarized, as
halogens are more electronegative than
carbon. Due to the high electronegativity of
 halogen, it attracts the electron cloud more
towards itself and thus gains a slight negative
charge, on the other hand, carbon obtains a
slight positive charge.
 As halogens need only one electron to achieve
their nearest noble gas configuration, only
one sigma bond is formed between one carbon
and one halogen atom.
 Due to the increase in atomic size from
fluorine to astatine, the C-X bond length in
haloarenes increases from fluorine to astatine
and bond strength decreases resulting in a
decrease in bond dissociation enthalpy.
 The dipole moment depends on the difference
in electronegativity of carbon and halogens
(group 17 trends properties) and as we know
that the electronegativity of halogens
decreases down the group, the dipole moment
also decreases. There is an exception to C-Cl
and C-F dipole moments. Though the
electronegativity of Cl is less than F, the
dipole moment of a C-Cl bond is more than C-
F.
Physical & Chemical Properties of
Haloalkanes and Haloarene
Physical Properties of Haloalkanes
Haloalkanes are hydrocarbons in
which hydrogen in a normal alkane is
replaced by a halogen (group 17
elements).
In this article, we will discuss the
physical properties of haloalkanes. The
physical properties of haloalkanes are
mostly like a normal covalent
compound. Halogens not being much
reactive functional group as a carboxyl
group or aldehyde doesn’t affect the
overall physical properties as much.
Still, few differences can be seen as we
move down in the homologous series of
the haloalkanes group due to the
difference in atomic masses of the
compound.
1. Notable Fact
The The physical properties of any
compound depend largely on
1. Its mass.
2. The type of intermolecular and
intramolecular forces of attraction.
2. Melting Point and Boiling Point of
Haloalkanes
There is a large electronegativity
difference between halogens and carbon
resulting in highly polarised molecules.
The higher molecular mass and greater
polarity as compared to the parent
hydrocarbon results in stronger
intermolecular forces of attraction
(dipole-dipole and van der Waals) in
the halogen derivatives. The boiling
Point depends upon the intermolecular
forces of attraction and hence the
boiling points of chlorides, bromides
and iodides are considerably higher
than those of the hydrocarbons of
comparable molecular mass.
As we go down in homologous series of
haloalkanes, the forces of attraction
become stronger due to the increase in
molecular size and mass, hence the
boiling point increases down the
homologous series. But the boiling
point decreases with branching.
Know more about the Nomenclature of
Haloalkanes
The melting point of a compound
depends upon the strength of the lattice
structure of a compound. The melting
point also follows the same trend as the
boiling point. An exception to this is
para-isomers. The para-isomers have
higher melting as compared to
their ortho and meta-isomers. It is due
to the symmetry of para-isomers that
fits in the crystal lattice better as
compared to ortho– and meta-isomers.
3. Density of Haloalkanes
Density is directly proportional to the
mass of the compound, hence down the
homologous series, density increase due
to increase in the mass, also fluoro
derivatives are less dense than chloro
derivatives; chloro derivatives are less
dense than bromo derivatives and so on.
4. Solubility of Haloalkanes
Haloalkanes are slightly soluble in
water. This is because of the relatively
larger amount of energy required to
break the bond between halogen and
carbon and the smaller amount of
energy released when the bond is
formed after the dissolution of ion and
water.
Chemical Properties of Haloalkanes
Haloalkanes are quite reactive
compounds. They undergo substitution,
elimination and reduction reactions.
They also react with some metals to
form organometallic compounds. The
reactivity of haloalkanes is mainly due
to the polar nature of the carbon
halogen bond.
The stability of alkyl halides generally
decreases as the strength of the C-X
bond decreases. Iodides generally
liberate iodine due to their low stability
and acquire brown or violet colour.
2R-I → R-R + I2 .