Which of the following statements is incorrect for a homologous series?

Options

A. There is a difference of `CH_3` between two consecutive homologous
B. Most of the members of a homologous series are prepared by similar methods
C. The members may be represented by a general formula
D. None of the above

Explanation

To determine which statement is incorrect regarding a homologous series, let's analyze the provided options step by step.

### Step 1: Understand the definition of a 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.

### Step 2: Analyze the first statement
**Statement 1:** "There is a difference of CH3 between two consecutive homologous series."
- In a homologous series, each successive member differs from the previous one by a constant unit. For alkanes, for example, the difference is CH2 (not CH3).
- Therefore, this statement is incorrect.

### Step 3: Analyze the second statement
**Statement 2:** "Most of the members of a homologous series are prepared by similar methods."
- This statement is true. Members of a homologous series often share similar chemical properties and can be synthesized using similar methods.

### Step 4: Analyze the third statement
**Statement 3:** "The members may be represented by a general formula."
- This statement is also true. For example, the general formula for alkanes is CnH2n+2, where 'n' is the number of carbon atoms. This formula applies to all members of the alkane homologous series.

### Conclusion
After analyzing all the statements:
- The first statement is incorrect because the difference between two consecutive members in a homologous series is CH2, not CH3.
- The second and third statements are correct.

Thus, the incorrect statement is: **"There is a difference of CH3 between two consecutive homologous series."**

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