chapter 4 carbon and its compound dec 2015 | Page 6

Homologous Series:
–

It is a series of compounds in which the same functional group substitutes for
hydrogen in a Carbon chain.

–

For instance, the ALCOHOLSs: CH3 OH, C2H5 OH, C3H7 OH, C4H9 OH.

–

The successive member differs by –CH2-; unit and 14 units of mass.

–

The chemical properties are imparted by the functional group thus all members
have similar chemical properties. But the members have different physical
properties.

–

The physical properties vary among the members of homologous series due
to difference in their molecular mass.

–

Melting point and boiling point increases with increasing molecular mass.

Nomenclature of Carbon Compounds:
1.
Identify the number of carbon atoms in the compound.
2.
Functional group is indicated either by prefix or suffix.
Functional Group
Suffix
Prefix
Alkene
ene
Alkyne
yne
Alcohol
ol
Aldehyde
al
Ketone
one
Carboxylic acid
oic acid
chlorine
chloro
36

X – Science

AK