The difference in molecular weight of two consecutive members of a homologous series is

Options

A. 15
B. 14
C. 8
D. 9

Explanation

To solve the question regarding the difference in molecular weight of two consecutive members of a homologous series, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the 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 specific structural unit, typically a -CH2- group.

2. **Identify the Difference in Molecular Formula**:
- The difference between two consecutive members of a homologous series is represented by the addition of a -CH2- unit. This means that if you have one member with the formula CnH2n+2, the next member will be C(n+1)H(2(n+1)+2).

3. **Calculate the Molecular Weight of the -CH2- Unit**:
- The molecular weight of a -CH2- unit can be calculated as follows:
- Carbon (C) has an atomic mass of approximately 12 g/mol.
- Hydrogen (H) has an atomic mass of approximately 1 g/mol.
- Therefore, the molecular weight of -CH2- is:
\[ \text{Molecular weight of -CH2-} = 12 + (2 \times 1) = 12 + 2 = 14 \text{ g/mol} \]

4. **Conclusion**:
- The difference in molecular weight between two consecutive members of a homologous series is 14 g/mol.

### Final Answer:
The difference in molecular weight of two consecutive members of a homologous series is **14 g/mol**.