` CH_(2)= CHCH_(2)CH=CH_(2) overset(NBS)rarr X(` Major `),(X)` is `:`

Options

A.
B. `CH_(20=CH-CH=CH-CH_(2)-Br`
C. `CH_(2)=CHCH_(2)CH=CHBr`
D.

Explanation

To solve the question regarding the reaction of the compound \( CH_2=CHCH_2CH=CH_2 \) with NBS (N-bromosuccinimide), we will follow these steps:

### Step 1: Identify the Reactant
The reactant is \( CH_2=CHCH_2CH=CH_2 \), which is a conjugated diene.

### Step 2: Understand the Role of NBS
NBS is used for bromination at the allylic position. The allylic position refers to the carbon atoms adjacent to the carbon-carbon double bond.

### Step 3: Identify the Allylic Positions
In the given diene, the allylic positions are:
- The carbon atoms adjacent to the double bonds.
- For the first double bond \( CH_2=CH \), the allylic carbon is \( CH_2 \) (the carbon connected to the double bond).
- For the second double bond \( CH=CH_2 \), the allylic carbon is \( CH_2 \) (the carbon connected to the double bond).

### Step 4: Mechanism of Reaction
The bromination occurs via a free radical mechanism:
1. NBS generates bromine radicals.
2. The bromine radical can attack the allylic carbon, leading to the formation of a radical at that position.

### Step 5: Determine the Major Product
1. If bromination occurs at the first allylic position (the first \( CH_2 \)):
- The product formed will be \( CH_2=CHCHBrCH=CH_2 \).
2. If bromination occurs at the second allylic position (the second \( CH_2 \)):
- The product formed will be \( CH_2=CHCH=CHBrCH_2 \).

### Step 6: Resonance Stabilization
- The radical formed by bromination at the second allylic position is more stable due to resonance.
- The resonance structures allow for delocalization of the radical, making it more stable than the radical formed at the first allylic position.

### Step 7: Conclusion
The major product formed from the reaction of \( CH_2=CHCH_2CH=CH_2 \) with NBS is:
\[ CH_2=CHCH=CHCH_2Br \]

### Final Answer
Thus, the major product \( X \) is \( CH_2=CHCH=CHCH_2Br \).

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