Question

How can you say that glucose is cyclic compound?

• A. Glucose undergoes Tollen's reaction
• B. Glucose reacts with phenyl hydrazine
• C. Glucose fails to react with sodium hydrogen sulphite
• D. Glucose reacts with nitric acid

Answer 1

Answer: (C)

Glucose fails to react with sodium hydrogen sulphite

Answer 2

Despite having the aldehyde group, glucose does not give 2,4,-DNP test. Schiff's test and it does not form the hydrogen sulphite addition product with $NaHS0_3$. It indicates the absence of free -CHO group.