`CH_(2)=CH-CH=CH-CH=CH_(2)`
How many geometrical isomers ar possible for this compound ?

Options

A. 2
B. 3
C. 4
D. 8

Explanation

To determine the number of geometrical isomers for the compound \( CH_2=CH-CH=CH-CH=CH_2 \), we will follow these steps:

### Step 1: Identify the Structure
The compound is a linear chain of six carbon atoms with alternating double bonds. It can be represented as:
\[ \text{C}_1 \text{C}_2 \text{C}_3 \text{C}_4 \text{C}_5 \text{C}_6 \]
where \( C_2, C_4, \) and \( C_6 \) are involved in double bonds.

### Step 2: Identify SP2 Hybridized Carbons
Geometrical isomerism occurs in compounds with at least two SP2 hybridized carbons. In this compound, the carbons involved in double bonds (C2, C4, and C6) are SP2 hybridized.

### Step 3: Check for Different Groups on SP2 Carbons
For geometrical isomerism to occur, the SP2 hybridized carbons must have different groups attached. We analyze the double bond positions:
- **C2**: Attached to \( H \) and \( CH_2=CH \) (different groups)
- **C4**: Attached to \( H \) and \( CH \) (different groups)
- **C6**: Attached to \( H \) and \( H \) (same groups)

Since C6 has two identical hydrogen atoms, it does not contribute to geometrical isomerism.

### Step 4: Identify Possible Isomers
The relevant double bonds for geometrical isomerism are at C2=C3 and C4=C5. Each of these double bonds can exhibit cis and trans configurations:
- **C2=C3** can be cis or trans.
- **C4=C5** can also be cis or trans.

However, since C6 does not contribute to geometrical isomerism, we only consider the configurations of the two double bonds.

### Step 5: Count the Isomers
The two double bonds can give rise to the following combinations:
1. **Cis-Cis**
2. **Cis-Trans**
3. **Trans-Cis**
4. **Trans-Trans**

However, since C6 does not allow for geometrical isomerism, we can only have:
- **Cis** and **Trans** configurations for the double bonds at C2=C3 and C4=C5.

Thus, the total number of geometrical isomers is **2** (one cis and one trans).

### Final Answer
The total number of geometrical isomers possible for the compound \( CH_2=CH-CH=CH-CH=CH_2 \) is **2**.

---