The number of chiral carbon in one molecule of `alpha`-D glucose is _______ .

Answer

To determine the number of chiral carbons in one molecule of alpha-D-glucose, we can follow these steps:

### Step 1: Understand the Definition of Chiral Carbon
A chiral carbon atom is one that is attached to four different groups. This means that if any two groups attached to the carbon are the same, that carbon is not chiral.

### Step 2: Draw the Structure of Alpha-D-Glucose
Alpha-D-glucose has a specific cyclic structure. It consists of six carbon atoms, and we need to visualize or draw the cyclic hemiacetal form of glucose.

### Step 3: Identify Each Carbon Atom
In the cyclic structure of alpha-D-glucose:
- Carbon 1 (C1) is the anomeric carbon where the hydroxyl (OH) group is on the right side, indicating it is alpha-D-glucose.
- Carbon 2 (C2)
- Carbon 3 (C3)
- Carbon 4 (C4)
- Carbon 5 (C5)
- Carbon 6 (C6) is part of the CH2OH group.

### Step 4: Analyze Each Carbon for Chirality
- **C1**: Attached to OH, H, CH2OH, and the ring structure (four different groups) - **Chiral**
- **C2**: Attached to OH, H, CH2OH, and the ring structure (four different groups) - **Chiral**
- **C3**: Attached to OH, H, CH2OH, and the ring structure (four different groups) - **Chiral**
- **C4**: Attached to OH, H, CH2OH, and the ring structure (four different groups) - **Chiral**
- **C5**: Attached to OH, H, CH2OH, and the ring structure (four different groups) - **Chiral**
- **C6**: Attached to OH and two H atoms (not four different groups) - **Not chiral**

### Step 5: Count the Chiral Carbons
From the analysis, we find that C1, C2, C3, C4, and C5 are chiral. Therefore, there are a total of **5 chiral carbons** in one molecule of alpha-D-glucose.

### Final Answer
The number of chiral carbon in one molecule of alpha-D-glucose is **5**.

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