The number of stereoisomers possible for a compound of the molecular formula `CH_(3)-CH=CH-CH(OH)-Me` is

Options

A. 3
B. 2
C. 4
D. 6

Answer

To determine the number of stereoisomers for the compound with the molecular formula `CH3-CH=CH-CH(OH)-CH3`, we will follow these steps:

### Step 1: Identify the Structure
The compound can be represented as:
- CH3-CH=CH-CH(OH)-CH3

This indicates that we have a 5-carbon chain with a double bond between the second and third carbons and a hydroxyl (OH) group on the fourth carbon.

### Step 2: Identify the Double Bond
The double bond between the second and third carbons (C2=C3) can give rise to geometric (cis/trans) isomerism.

### Step 3: Determine the Configuration of the Double Bond
For the double bond C2=C3:
- If both substituents on C2 and C3 are the same, it will not lead to stereoisomerism.
- In our case, C2 has CH3 and CH (from CH(OH)-CH3) as substituents, and C3 has CH and CH3. Therefore, we can have two configurations:
- **Cis**: Both CH3 groups are on the same side.
- **Trans**: CH3 groups are on opposite sides.

### Step 4: Identify the Chiral Center
The carbon atom at C4 (the one attached to the hydroxyl group) is a chiral center because it has four different substituents:
1. CH3
2. OH
3. CH (from the double bond)
4. H

### Step 5: Calculate the Total Number of Stereoisomers
The number of stereoisomers can be calculated using the formula:
\[ \text{Total Stereoisomers} = 2^n \]
where \( n \) is the number of chiral centers plus the number of geometric isomers.

- We have 1 chiral center (C4).
- We have 2 geometric isomers (cis and trans for the double bond).

Thus, the total number of stereoisomers is:
\[ \text{Total Stereoisomers} = 2^1 \times 2 = 2 \times 2 = 4 \]

### Conclusion
The number of stereoisomers possible for the compound `CH3-CH=CH-CH(OH)-CH3` is **4**.

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