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 CH3
\ /
C = C
/ \
H H
```
In this structure, the two methyl groups (CH3) are on opposite sides of the double bond.

### Step 2: Identify the Reaction Conditions
The bromination of trans-2-butene is typically carried out using bromine (Br2) in a non-polar solvent like carbon tetrachloride (CCl4). This reaction leads to the addition of bromine across the double bond.

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

### Step 4: Draw the Possible Products
When bromine adds to trans-2-butene, we can visualize the addition as follows:
1. One bromine atom adds to one carbon of the double bond.
2. The second bromine atom adds to the other carbon of the double bond, but on the opposite side due to anti-addition.

This results in the following structure:
```
CH3 CH3
\ /
C - Br
/ \
Br H
```

### Step 5: Analyze the Stereochemistry
The product formed from the bromination of trans-2-butene has a plane of symmetry, making it a meso compound. A meso compound is one that has multiple stereocenters but is superimposable on its mirror image due to internal symmetry.

### Step 6: Count the Stereoisomers
Since the product is a meso compound, it does not have any enantiomers. Therefore, the total number of stereoisomers formed from the bromination of trans-2-butene is **1**.

### Final Answer
The number of stereoisomers obtained by bromination of trans-2-butene is **1**.

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