The major product of the following reaction is:
`CH_3underset(Br)underset(|)CHCH_2underset(Br)underset(|)CHCH_2CH_3overset(KOH,CH_3OH)underset(heat)rarr`

Options

A. `CH_2=CHCH_2CH=CHCH_3`
B. `CH_2=CHCH=CHCH_2CH_3`
C. `CH_3CH=C=CHCH_2CH_3`
D. `CH_3CH=CH-CH=CHCH_3`

Explanation

To determine the major product of the given reaction, we will follow these steps:

### Step 1: Identify the Reactants
The reactants are:
- 1-bromo-2-methylbutane (CH3-CHBr-CH2-CHBr-CH2-CH3)
- KOH in methanol with heat

### Step 2: Understand the Reaction Type
The presence of KOH (a strong base) and heat suggests that this reaction will undergo an elimination reaction (E2 mechanism), where bromine (Br) will be eliminated along with a hydrogen atom (H) to form a double bond.

### Step 3: Identify the Possible Elimination Sites
In the structure, we have two bromine atoms that can be eliminated:
1. The bromine on the first carbon (1-bromo)
2. The bromine on the second carbon (2-bromo)

### Step 4: Determine the Elimination Pathway
- If the bromine on the first carbon is eliminated, the hydrogen from the adjacent carbon (the second carbon) will be abstracted, leading to the formation of a double bond between the first and second carbons.
- If the bromine on the second carbon is eliminated, the hydrogen from the adjacent carbon (the third carbon) will be abstracted, leading to the formation of a double bond between the second and third carbons.

### Step 5: Analyze the Stability of the Alkenes Formed
- **Elimination of Br from the first carbon**:
- Forms CH2=CH-CH2-CH2-CH3 (1-pentene)
- **Elimination of Br from the second carbon**:
- Forms CH3-CH=CH-CH2-CH3 (2-pentene)

The stability of alkenes is influenced by the number of alkyl substituents on the double bond. The more substituted the double bond, the more stable the alkene.

### Step 6: Determine the Major Product
In this case, 2-pentene (formed by the elimination of Br from the second carbon) is more stable than 1-pentene because it is more substituted (the double bond is between the second and third carbons, which has more alkyl groups attached).

### Conclusion
The major product of the reaction is **2-pentene (CH3-CH=CH-CH2-CH3)**.

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