How many stereoisomerse does this molecule has?
`CH_(3)CH=CHCH_(2)CHBrCH_(3)`

Options

A. 8
B. 2
C. 4
D. 6

Explanation

To determine the number of stereoisomers for the molecule \( CH_3CH=CHCH_2CHBrCH_3 \), we will follow these steps:

### Step 1: Draw the Structure
First, we need to draw the structure of the given molecule. The molecule can be represented as follows:

```
CH3
|
C = C
| |
CH2 CH
| |
CH3 Br
```

### Step 2: Identify Geometrical Isomers
Next, we need to identify if the molecule has geometrical (cis-trans) isomers. The double bond between the second and third carbon atoms (C=C) allows for cis and trans configurations.

- **Cis Isomer**: The bromine (Br) and the methyl (CH3) groups are on the same side of the double bond.
- **Trans Isomer**: The bromine (Br) and the methyl (CH3) groups are on opposite sides of the double bond.

Thus, we have two geometrical isomers:
1. Cis isomer
2. Trans isomer

### Step 3: Identify Chiral Centers
Next, we need to check for chiral centers in the molecule. A chiral center is a carbon atom that is attached to four different groups.

In this molecule, the carbon atom adjacent to the bromine (the fourth carbon) is a chiral center because it is attached to:
- A bromine (Br)
- A hydrogen (H)
- A methyl group (CH3)
- A propyl group (CH2CH3)

### Step 4: Calculate Optical Isomers
The number of optical isomers is calculated using the formula \( 2^n \), where \( n \) is the number of chiral centers. In this case, there is 1 chiral center.

\[ \text{Number of optical isomers} = 2^1 = 2 \]

### Step 5: Total Stereoisomers
Finally, the total number of stereoisomers is the sum of the geometrical and optical isomers:

\[ \text{Total stereoisomers} = \text{Number of geometrical isomers} + \text{Number of optical isomers} = 2 + 2 = 4 \]

### Conclusion
The total number of stereoisomers for the molecule \( CH_3CH=CHCH_2CHBrCH_3 \) is **4**.

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