The number of optical isomers of 2,3 - dihydroxy butanal is/are

Options

A. Two
B. Three
C. Four
D. One

Explanation

To determine the number of optical isomers of 2,3-dihydroxybutanal, we will follow these steps:

### Step 1: Identify the Structure of 2,3-Dihydroxybutanal
2,3-Dihydroxybutanal is an aldehyde with two hydroxyl (–OH) groups on the second and third carbon atoms. The molecular formula is C4H8O3. The structure can be represented as follows:

```
CHO
|
CH(OH)
|
CH(OH)
|
CH3
```

### Step 2: Determine the Chiral Centers
A chiral center is a carbon atom that is bonded to four different groups. In the case of 2,3-dihydroxybutanal, we need to examine the second and third carbon atoms:

- **Second Carbon (C2)**: It is attached to –OH, –H, –CH3, and the carbon chain (C3). Thus, it is a chiral center.
- **Third Carbon (C3)**: It is attached to –OH, –H, –CHO, and the carbon chain (C2). Thus, it is also a chiral center.

Both C2 and C3 are chiral centers.

### Step 3: Calculate the Number of Optical Isomers
The formula to calculate the number of optical isomers is given by:
\[ \text{Number of optical isomers} = 2^n \]
where \( n \) is the number of chiral centers.

In our case, we have:
- \( n = 2 \) (two chiral centers)

Thus, the number of optical isomers is:
\[ 2^2 = 4 \]

### Conclusion
The number of optical isomers of 2,3-dihydroxybutanal is **4**.

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