What is homologous series in chemistry?

Answer 1

This is part of organic chemistry.

Homologous Series: is a series of compounds with the SAME GENERAL FORMULA, SIMILAR CHEMICAL PROPERTIES, and a GRADUATION IN PHYSICAL PROPERTIES, where each member differs from the previous member by a CH2 group.

For example:

ALKANES: General formula is C(n)H(2n+2) eg. C2H6 or C3H8 or C4H10.

All of these are saturated molecules, so they contain the maximum number of hydrogen atoms per molecule, ie. all bonds are single and there are no unused electron pairs.

This means that these will not be able to undergo addition reactions because there are no free electron pairs to bond to. Therefore, alkanes have SIMILAR

CHEMICAL PROPERTIES. Also, no alkane is polar.

Alkanes have a GRADUATION IN PHYSICAL PROPERTIES because as there are more CH2 groups, the molecule's mass and size increases, hence the

strength of the acting intermolecular forces, the Van der Waal's forces is

increasing therefore the bigger the molecule, the stronger the intermolecular forces, therefore the higher the boiling point.

Answer 2

1. STRUCTURAL FORMULA

All the members of a homologous series have same structural formula.

2. MOLECULAR FORMULA

Molecular formula of different members of a homologous series differs from previous and next member by CH2.

3. NATURE OF ELEMENT

All the members of series have same type of elements.

4. FUNCTIONAL GROUP

All the members of homologous series contain same functional group.

5. GENERAL FORMULA

Members of a homologous series can be represented by a general formula.

FOR EXAMPLE:

ALKANE : CnH2n+2

ALKENE : CnH2n

ALKYNE : CnH2n-2

ALCOHOL : CnH2n+1-OH

ETHERS : CnH2nO

Where n = number of carbon atoms.

6. MOLECULAR MASS

Molecular mass of any two consecutive members differ by 14 units

7. CHEMICAL PROPERTIES

All the members of a homologous series have same chemical properties due to same functional group.

8. METHODS OF PREPARATION

Generally all the members of a series can be prepared by using same method.

9. PHYSICAL PROPERTIES

Physical properties of the members of a homologous series vary with the increase in atomic weight.

Answer 3

Because they have the same functional group.

Answer 4

A series of organic compounds in which two successive members are differ by CH2.

Answer 5

Compounds is a homologous series differ from each other by one constant unit.

Answer 6

because they are the same natures

Answer 7

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