Page 21 - Pharm.Org.Chem-I 02-06-05-101

Alkanes (Paraffins)

General formula: CnH2n+2

number of C atoms name Structure

1 methane CH4
2 ethane CH3CH3
3 CH3CH2CH3
4 n- propane CH3(CH2)2CH3
5 n- butane CH3(CH2)3CH3
6 n-pentane CH3(CH2)4CH3
7 hexane CH3(CH2)5CH3
8 heptane CH3(CH2)6CH3
9 CH3(CH2)7CH3
10 octane CH3(CH2)8CH3
nonane

decane

Alkane - H Alkyl e.g. methane - H methyl

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1- Select the longest chain of hydrocarbons.
2- Number the longest chain from the end nearest
to the branch so that side chain would take lowest
possible no.

6 5 4 3 21

CH3CH2CH2CH2CHCH3
12 34 5

7 6 54 3 CH2CH3

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2-Ethylhexane X 21
5-Methylheptane X

3-Methylheptane

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