IUPAC nomenclature of Organic chemistry - cbse24

 Carbon compounds can be classified into two types.

1:-Trivial or common system

2:-IUPAC system

1:-Trivial or common system

  • The name of HCOOH is formic acid because the first time it is found in ants and this ant's Latin name is Formica.
  • Methane's name is marsh gas because it is found in marshy areas.
  • In mammals' urine NH2CONH2 find. Later that name puts urea.

2:-IUPAC System(International union of pure and applied chemistry)

The nomenclature of IUPAC of any carbonic compound has three parts.
(a) Word root    (b) Suffix   (c) Prefix

(a) Word root:-

Word root

The Word root of the IUPAC name indicates the number of carbon atoms in the longest possible continuous carbon chain also known as the parent chain chosen by a set of rules.

(b) Suffix:-

 Suffix are two types

(1) Primary Suffix            (2) Secondary Suffix

(1)Primary Suffix:-
  • (―) 'ane'
  • (≓)  'ene'
  • (☰) 'yne'
(2) Secondary Suffix:-

Secondary Suffix

(c) Prefix:-

A prefix is also two types

(1) Primary Prefix             (2) Secondary Prefix

(1) Primary Prefix
Primary Prefix

This is used to put the difference between cyclic compound and acyclic compound.

(2) Secondary Prefix

Secondary Prefix


Secondary Prefix+Primary Prefix+Word Root+Primary Suffix+Secondary Suffix

(I) The naming of Saturated hydrocarbons
Example of Saturated Hydrocarbon

(II) IUPAC Nomenclature for Branched-chain Saturated Hydrocarbon

Example of Branched-Chain Saturated Hydrocarbon

(III) The naming of unsaturated hydrocarbons containing a double bond

Example of Unsaturated Hydrocarbon Containing Double Bond

(IV) The naming of unsaturated hydrocarbons containing a triple bond
Example of Unsaturated Hydrocarbon Containing Triple Bond


  • In inorganic chemistry, a given molecular formula represents only one compound Ex:-H2SO4.
  • Inorganic chemistry, however, a given molecular formula can represent two or more different compounds.
  • The organic compound has the same molecular formula but a different structure are known as isomers
Ex:-Consider an organic compound C4H10 called butane.

(i) First, all the four carbon atoms are joined in a continuous straight chain.

(ii) In the second case, three carbons atoms can be put in the straight-chain and the fourth carbon atom can be joined in the side chain.

  • We find that both n-butane(normal- butane) & iso-butane have the same molecular formula(C4H10) but different structures. They are called isomers.
  • The butane fuel present in LPG cylinders is a mixture of both its isomers:-n-butane and iso-butane(LPG also contain a smaller amount of propane &ethane)


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