State true or false: in homologous series all the members have the same physical prperties

Answer

To determine whether the statement "In homologous series, all the members have the same physical properties" is true or false, we can analyze the characteristics of homologous series in organic chemistry.

### Step-by-Step Solution:

1. **Understanding Homologous Series**:
- A homologous series is a group of organic compounds that have the same functional group and similar chemical properties, but differ by a constant unit, typically a -CH2- group.

2. **Chemical Properties**:
- Members of a homologous series exhibit similar chemical properties due to the presence of the same functional group. For example, all alkanes have similar reactivity patterns because they all contain only single C-C bonds.

3. **Physical Properties**:
- Physical properties include characteristics such as boiling point, melting point, density, and solubility.
- These properties are influenced by the molecular mass and structure of the compounds.

4. **Effect of Molecular Mass**:
- As you move through a homologous series, the molecular mass increases due to the addition of -CH2- units.
- The increase in molecular mass affects physical properties. For example, boiling points and melting points generally increase with increasing molecular mass because of stronger London dispersion forces (a type of van der Waals force) in larger molecules.

5. **Conclusion**:
- Since the physical properties vary with the increase in molecular mass, it is incorrect to say that all members of a homologous series have the same physical properties.
- Therefore, the statement is **false**.

### Final Answer:
The statement "In homologous series, all the members have the same physical properties" is **False**.