When the following aldohexose exists in its D-configuration, the total number of stereoisomers in its pyranose form, is
`{:(CHO),(|),(CHOH),(|),(CHOH),(|),(CHOH),(|),(CHOH),(|),(CH_(2)OH):}`

Options

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

Answer

To determine the total number of stereoisomers for the given aldohexose in its D-configuration when it exists in its pyranose form, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Structure of Aldohexose**:
- An aldohexose is a six-carbon sugar with an aldehyde group at one end. The general formula is C6H12O6.
- The D-configuration indicates that the hydroxyl group (-OH) on the last chiral carbon (C5) is on the right side in a Fischer projection.

2. **Convert to Pyranose Form**:
- The pyranose form is a cyclic structure formed when the aldehyde group reacts with one of the hydroxyl groups. For aldohexoses, this typically involves the reaction between the aldehyde carbon (C1) and the hydroxyl group on C5.
- In the pyranose form, the structure will include an oxygen atom in the ring and will be a six-membered ring.

3. **Identify Chiral Carbons**:
- In the pyranose form of D-aldohexose, we need to identify the chiral centers.
- The chiral carbons in the pyranose form are typically at C2, C3, C4, and C5.
- Thus, there are 4 chiral centers in the pyranose form.

4. **Calculate the Total Number of Stereoisomers**:
- The formula for calculating the number of stereoisomers based on the number of chiral centers (n) is given by \(2^n\).
- Here, n = 4 (the number of chiral centers).
- Therefore, the total number of stereoisomers is \(2^4 = 16\).

5. **Conclusion**:
- The total number of stereoisomers in the pyranose form of the given D-aldohexose is 16.

### Final Answer:
The total number of stereoisomers in the pyranose form of the given D-aldohexose is **16**.