What is the number of asymmetric carbon atoms present in `alpha`-D-glucopyranose molecule?

Options

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

Explanation

To determine the number of asymmetric carbon atoms in the alpha-D-glucopyranose molecule, we can follow these steps:

### Step 1: Understand the Structure of Alpha-D-Glucopyranose
Alpha-D-glucopyranose is a cyclic form of glucose. It is a six-membered ring structure (pyranose) formed by the reaction of the aldehyde group with one of the hydroxyl groups.

### Step 2: Identify the Carbon Atoms
In the structure of alpha-D-glucopyranose, there are six carbon atoms. The carbon atoms are numbered from C1 to C6.

### Step 3: Determine Chirality
A carbon atom is considered asymmetric (or chiral) if it is attached to four different groups. We will analyze each carbon atom in the structure:

- **C1**: Attached to -OH, -H, -CH2OH (from C6), and -C2 (ring structure) - **Chiral**
- **C2**: Attached to -OH, -H, -C1, and -C3 - **Chiral**
- **C3**: Attached to -OH, -H, -C2, and -C4 - **Chiral**
- **C4**: Attached to -OH, -H, -C3, and -C5 - **Chiral**
- **C5**: Attached to -OH, -H, -C4, and -C6 (ring structure) - **Chiral**
- **C6**: This carbon is attached to two hydrogens and one hydroxyl group, making it not chiral.

### Step 4: Count the Asymmetric Carbon Atoms
From the analysis, we find that C1, C2, C3, C4, and C5 are all chiral. Therefore, there are a total of 5 asymmetric carbon atoms in alpha-D-glucopyranose.

### Final Answer
The number of asymmetric carbon atoms present in alpha-D-glucopyranose is **5**.

---