The number of stereoisomers obtained by bromination of trans-2-butene is :

Options

A. 1
B. 2
C. 3
D. 4

Explanation

To determine the number of stereoisomers obtained by the bromination of trans-2-butene, we can follow these steps:

### Step 1: Understand the Structure of trans-2-butene
Trans-2-butene has the following structure:

```
CH3
|
H3C-C=C-CH3
|
H
```

In this structure, the two methyl groups (CH3) are on opposite sides of the double bond, which gives it its trans configuration.

### Step 2: Identify the Reaction
When trans-2-butene undergoes bromination, it reacts with bromine (Br2). This reaction involves the addition of bromine across the double bond.

### Step 3: Determine the Mechanism of Bromination
The bromination of alkenes typically proceeds via an anti-addition mechanism. This means that the bromine atoms will add to opposite sides of the double bond.

### Step 4: Draw the Product
When bromine adds to trans-2-butene, the product formed will have the bromine atoms added to opposite sides of the double bond. The resulting structure can be represented as follows:

```
CH3
|
H3C-C-Br
|
Br
```

### Step 5: Analyze for Stereoisomers
In this case, the product formed is a meso compound. A meso compound is a molecule that has multiple stereocenters but is superimposable on its mirror image due to an internal plane of symmetry.

### Step 6: Conclusion
Since the product is a meso compound, it does not have any stereoisomers. Therefore, the number of stereoisomers obtained by the bromination of trans-2-butene is **1** (the meso compound itself).

### Final Answer
The number of stereoisomers obtained by bromination of trans-2-butene is **1** (the meso compound).

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