Question

Which one of the following features/properties does glucose acquire through intramolecular hemiacetal formation?

• A. Ability to function as a reducing agent
• B. An additional chiral carbon
• C. Ability to form anhydride linkage with non-carbohydrate moieties such as the inorganic phosphate
• D. Ability to form epimers

Hint:

When sugars cyclize, the carbonyl carbon becomes asymmetric — forming α and β anomers. This new asymmetric carbon is called the {anomeric carbon}.

Answer 1

The Correct Option is B

Step 1: Recall the structure of glucose.
In its open-chain form, glucose contains an aldehyde group and five hydroxyl groups.
Step 2: Formation of intramolecular hemiacetal.
When glucose cyclizes, the hydroxyl group on C-5 reacts with the aldehyde group at C-1 to form a hemiacetal.
This results in a six-membered ring (pyranose form).
Step 3: Identify the change in chirality.
The carbonyl carbon (C-1), which was achiral in the open-chain form, now becomes a new chiral center after ring formation.
This leads to two possible stereoisomers, called α- and β-anomers.
Step 4: Conclusion.
Thus, during intramolecular hemiacetal formation, glucose gains an additional chiral carbon.