Number of optically inactive stereoisomers of the following molecule is .
`CH_3-CH=CH-undersetunderset(OH)(|)CH-CH=CH-undersetunderset(OH)(|)CH-CH=CH-CH_3`

Explanation

To determine the number of optically inactive stereoisomers for the given molecule, we will follow these steps:

### Step 1: Identify the Stereocenters
First, we need to identify the stereocenters in the molecule. A stereocenter is typically a carbon atom that is bonded to four different groups, allowing for different spatial arrangements (stereoisomers).

1. **Examine the structure**: The given molecule has multiple carbon atoms with hydroxyl (OH) groups and double bonds (alkenes).
2. **Count the stereocenters**: In this case, we find that there are 5 stereocenters in the molecule.

### Step 2: Use the Formula for Optically Inactive Isomers
The formula to calculate the number of optically inactive stereoisomers is given by:

\[ \text{Number of optically inactive isomers} = \frac{2^{n-1}}{2} \]

where \( n \) is the number of stereocenters.

1. **Substitute the value of n**: Here, \( n = 5 \).
2. **Calculate**:
\[ \text{Number of optically inactive isomers} = \frac{2^{5-1}}{2} = \frac{2^4}{2} = \frac{16}{2} = 8 \]

### Step 3: Conclusion
Thus, the number of optically inactive stereoisomers for the given molecule is **8**.

### Final Answer
The number of optically inactive stereoisomers of the given molecule is **8**.

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