Question

No. of optical isomers of glucose is:
A.8
B.16
C.32
D.4

Answer 1

Hint: Identify the number of chiral carbons to find how many stereoisomers exist. An arbitrary number (n) of chiral centres in a molecule there are as many as ${2^n}$ possible stereoisomers.

Complete step by step answer:
Let’s find the number of chiral carbons in glucose by drawing its structure.

Glucose has four chiral carbons in its aldehyde form, and so there are ${2^4}$ or 16 possible stereoisomers of this formula. These 16 isomers are:
1.

2. 

3. 

4.

5. 

6. 

7. 

8. 

9.

10.

11. 

12.

13.

14.

15.

   16.

Therefore, we can conclude that the correct answer to this question is option B.

Note:
The 16 stereoisomers of glucose along with their D and L forms. The isomers with their C-5 hydroxyl group on the right are called D-, the isomers with C-5 on the left are L-isomers. Each aldohexose is the diastereomer of the other 14 isomers.