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Answer:
1. ALKANES
(CnH2n + 2)
Formula
carbons (n) Name
Number of Number of
carbons (n) Name
Formula
(CnH2n + 2)
1
2
3
4
5
6
7
8
9
10
Methane
Ethane
Propane
Butane
Pentane
Hexane
Heptane
Octane
Nonane
Decane
CH4
C2H6
C3H8
C4H10
C5H12
C6H14
C7H16
C8H18
C9H20
C10H22
Table 1 Straight-chain alkane (n-alkane) names
The suffix -ane is added to the end of each name to show that the compound is an alkane. Thus,
butane is the four-carbon alkane, heptane is the seven-carbon alkane, and so on. The names of the first
ten alkanes, given in Table 1, should be memorized. Larger alkanes, such as icosane (C20H42), have
more complicated names and are outside the scope of this course.
If one hydrogen atom is removed from an alkane, the remaining part of the molecule is called an alkyl
group. Alkyl groups are named by replacing the -ane ending of the parent alkane by an -yl ending. For
example, removing a hydrogen atom from methane gives the methyl group. Similarly, removal of a
hydrogen from an end carbon of any n-alkane produces the series of straight-chain alkyl (n-alkyl)
groups show in Table 2.
Alkane Alkyl group
Table 2 Straight-chain alkyl (n-alkyl) groups
Alkane Alkyl group
CH4
CH3CH3
CH3CH2CH3
CH3CH2CH2CH3
Methane
Ethane
Propane
Butane
Methyl (Me)
Ethyl (Et)
Propyl(Pr)
Butyl (Bu)
(Abbreviations in parentheses)
CH3−
CH3CH2−
CH3CH2CH2− or n-C3H7
CH3CH2CH2CH2− or n-C4H9
Using the IUPAC (International Union of Pure and Applied Chemistry) rules, most branched-chain
alkanes can be named by the following four steps. For more complex alkanes, a fifth step is needed.
Step 1 Find the parent hydrocarbon
a) Find the longest continuous carbon chain present in the molecule and use the name of
that chain as the parent name.
Explanation: