2, 3-Dimethylbut-2-ene when reacted with bromine forms a compound which upon heating with alcoholic KOH produce the following major product.

Options

A.
B.
C.
D.

Explanation

To solve the problem, we will follow these steps:

### Step 1: Understand the structure of 2,3-Dimethylbut-2-ene
2,3-Dimethylbut-2-ene has the following structure:

```
CH3
|
CH3 - C = C - CH3
|
CH3
```

### Step 2: Reaction with Bromine
When 2,3-Dimethylbut-2-ene reacts with bromine (Br2), it undergoes an addition reaction, resulting in the formation of 2,3-Dibromo-2,3-dimethylbutane. The bromine atoms add across the double bond:

```
CH3
|
CH3 - C - Br - CH3
|
Br
```

### Step 3: Reaction with Alcoholic KOH
Next, when 2,3-Dibromo-2,3-dimethylbutane is treated with alcoholic KOH, an elimination reaction occurs. Alcoholic KOH acts as a strong base and removes a hydrogen atom from one of the carbons adjacent to the bromine, leading to the formation of a double bond:

1. The base abstracts a hydrogen atom from one of the carbon atoms adjacent to the bromine.
2. The electrons from the C-H bond form a double bond between the two carbon atoms, and the bromine leaves.

This results in the formation of a compound with a double bond:

```
CH3
|
CH3 - C = C - CH3
```

### Step 4: Identify the Major Product
The major product formed after the elimination reaction is 2,3-Dimethylbut-2-ene:

```
CH3
|
CH3 - C = C - CH3
|
CH3
```

### Final Answer
The major product formed when 2,3-Dimethylbut-2-ene is reacted with bromine and then treated with alcoholic KOH is **2,3-Dimethylbut-2-ene**.

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