The number of chiral centres in D-(+)-glucose is

Options

A. Five
B. Six
C. Three
D. Four

Answer

To determine the number of chiral centers in D-(+)-glucose, we can follow these steps:

### Step 1: Understand the Structure of D-(+)-Glucose
D-(+)-glucose is an aldohexose, meaning it is a six-carbon sugar with an aldehyde group at one end. The molecular formula is C6H12O6. The structure consists of a chain of six carbon atoms, with hydroxyl (OH) groups attached to some of the carbons.

### Step 2: Draw the Structure
1. Start with the aldehyde group (CHO) at the first carbon.
2. Draw the carbon chain: C1 (CHO) - C2 - C3 - C4 - C5 - C6 (CH2OH).
3. Attach the hydroxyl (OH) groups to the appropriate carbons based on the D-configuration.

### Step 3: Identify Chiral Centers
A chiral center is a carbon atom that has four different substituents. In D-(+)-glucose, we need to analyze each carbon atom:
1. **C1**: Aldehyde group (CHO), not chiral.
2. **C2**: Has OH, H, CH2OH, and C3. This is a chiral center.
3. **C3**: Has OH, H, C2, and C4. This is a chiral center.
4. **C4**: Has OH, H, C3, and C5. This is a chiral center.
5. **C5**: Has OH, H, C4, and CH2OH. This is a chiral center.
6. **C6**: CH2OH, not chiral.

### Step 4: Count the Chiral Centers
From the analysis:
- C2, C3, C4, and C5 are chiral centers.
- Therefore, there are a total of **4 chiral centers** in D-(+)-glucose.

### Conclusion
The number of chiral centers in D-(+)-glucose is **4**.

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