Homologous series english

Homologous series

It is noticed that the properties of  CH3OH, C2H5OH, C3H7OH are very similar, properties are similar because of having same functional group.

 But there is  difference in their physical property. This changes were because of different number of carbon and number of hydrogen.

Alkane ,alkene,alkyne  all three forms series in which there is difference by CH2 or 14 u by mass between consecutive members, this series is known as Homologous series 

This can be defined as

The series of compounds having same general formula and differ by 14 u by mass or CH2 between two consecutive members are called Homologous series.

For example:-

CH4.         In this series two consecutive          C2H5        members are differ by CH2 or 14 u.

C3H8        So this is a homologous series.

C4H10

C5H12

C6H14

C7H16

Let consider some physical properties between the homologous series of Alkanes.

1. First 4 member of Alkanes are colorless and odour less gases at room temperature. From 5th member to 17th member of this series are colorless liquids, where as members above 17 are waxy solid.
2. Boiling point gradually increases with increase in number of CH2

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