Page 18 - 10-Chem-11 Organic Chemistry

11. Organic Chemistry eLearn.Punjab

• Uses as Fuel: The fuels we use for automobiles and domestic purposes are coal, petroleum
and natural gas. These are called fossil fuels. All of these are organic compounds.

• Uses as Medicines: A large number of organic compounds (naturally synthesized by
plants) are used as medicines by us. Most of the life saving medicines and drugs such as
antibiotics (inhibit or kill microorganisms which cause infectious diseases) are synthesized
in laboratories.

• Uses as Raw Material: Organic compounds are used to prepare a variety of materials,
such as rubber, paper, ink, drugs, dyes, paints, varnishes, pesticides, etc.

TestYourself 11.3 1. Define petroleum.
2. What types of compounds are synthesized by plants?
3. What is the basic unit of carbohydrates and how is it synthesized?
4. CNG stands for ....
5. Our existence owes to organic compounds, comment.

11.4 ALKANES AND ALKYLRADICALS

Alkanes are saturated hydrocarbons or paraffins (para means little, affin means affinity).
Their general formula is C Hn 2n+2 , where ‘n’ is number of carbon atoms. In case of alkanes
‘n’ ranges from 1 to 40. In this way, alkanes form the most important homologous series of
compounds.

Homologous Series

Organic compounds are divided into groups of compounds having similar chemical properties.
Each group is known as a homologous series. Organic compounds of the same homologous
series have the following properties in common:

1. All members of a series can be represented by a general formula for example general
formulae of alkane, alkenes and alkynes are C Hn 2n+2 , CnH2n and CnH2n-2 , respectively.

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