Question

Different structural information about glucose can be derived by reacting it with different reagents. Which of the following is correct?

• A. Reaction with HI confirms the presence of carbonyl groups.
• B. Acetylation with acetic anhydride confirms the presence of -OH groups.
• C. Reaction with bromine water confirms a straight chain.
• D. Oxidation with nitric acid confirms the presence of secondary -OH groups.

Hint:

Glucose + 5 Acetic Anhydride $\rightarrow$ Pentaacetate. If it takes 5, there are 5 -OH groups!

Answer 1

The Correct Option is B

Step 1: Concept
Chemical tests are used to elucidate the structure of biomolecules like glucose by identifying specific functional groups.

Step 2: Analysis of Options
Reaction with HI/P yields n-hexane, confirming a straight chain. Bromine water (a mild oxidant) confirms the aldehyde group. Nitric acid (strong oxidant) confirms the primary alcohol group and the aldehyde.

Step 3: Correct Identification
Acetylation of glucose with acetic anhydride results in glucose pentaacetate, which confirms the presence of five hydroxyl (-OH) groups.

Step 4: Conclusion
The correct match is the use of acetic anhydride for -OH group confirmation. Final Answer: (B)