The major product obtained on treatment of `CH_(3)CH_(2)CH(F) CH_(3) " with " CH_(3)O^(-)//CH_(3)OH` is :

Options

A. `CH_(3)CH_(2)CH(OCH_(3))CH_(3)`
B. `CH_(3)CH=CHCH_(3)`
C. `CH_(3)CH_(2)CH=CH_(2)`
D. `CH_(3)CH_(2)CH_(2)CH_(2)OCH_(3)`

Explanation

To solve the problem, we need to determine the major product formed when `CH3CH2CHFCH3` is treated with `CH3O^-/CH3OH`. The reaction involves an elimination process, specifically dehydrohalogenation, where a halogen (in this case, fluorine) and a hydrogen atom are removed to form an alkene.

### Step-by-Step Solution:

1. **Identify the Reactants**: The reactant is `CH3CH2CHFCH3`, which is a fluorinated alkane. The base used is `CH3O^-` (methoxide ion) in methanol.

2. **Recognize the Reaction Type**: Since we have a halogen (fluorine) and a base, we can expect an elimination reaction to occur, specifically a dehydrohalogenation reaction.

3. **Determine Possible Elimination Sites**: In the compound `CH3CH2CHFCH3`, we can eliminate the fluorine atom and a hydrogen atom. The hydrogen can be removed from either of the two carbon atoms adjacent to the carbon bearing the fluorine.

4. **Apply Zaitsev's Rule**: According to Zaitsev's rule, the more substituted alkene will be the major product when a non-bulky base is used. We will analyze both possible elimination pathways:
- **Pathway 1**: Remove a hydrogen from the carbon next to the fluorine (the second carbon). This leads to the formation of `CH3CH=CHCH3` (butene).
- **Pathway 2**: Remove a hydrogen from the terminal carbon (the first carbon). This leads to the formation of `CH3CH2CH=CH2` (butene).

5. **Count the Number of Alpha Hydrogens**:
- For the first product (`CH3CH=CHCH3`), there are 6 alpha hydrogens (3 from the first carbon and 3 from the second carbon).
- For the second product (`CH3CH2CH=CH2`), there are only 2 alpha hydrogens (2 from the first carbon).

6. **Determine the Major Product**: Since the first product has more alpha hydrogens and is more substituted, it is more stable. Therefore, `CH3CH=CHCH3` is the major product.

7. **Select the Correct Answer**: Among the options provided, the correct answer is `CH3CH=CHCH3`.

### Final Answer:
The major product obtained on treatment of `CH3CH2CHFCH3` with `CH3O^-/CH3OH` is `CH3CH=CHCH3`.