Question

Which one of the following statements is TRUE with regard to glucose?

• A. It gives Schiff's test
• B. It forms addition product with $NaHSO_3$
• C. It does not undergo mutarotation
• D. Its pentaacetate does not react with $NH_2OH$
• E. B- form of glucose is obtained by crystallisation from conc. solution of glucose

Answer 1

The Correct Option is D

Let’s evaluate each statement about glucose to determine the correct one: 

• It gives Schiff's test: False. Glucose does not give a positive Schiff’s test because its aldehyde group is involved in the cyclic hemiacetal form.
• It forms addition product with \( NaHSO_3 \): False. Glucose generally does not form a stable addition product with sodium bisulfite due to its cyclic structure.
• Its pentaacetate does not react with \( NH_2OH \): True. In the pentaacetate form, the carbonyl group of glucose is blocked by acetylation, so it cannot react with hydroxylamine.
• It does not undergo mutarotation: False. Glucose does undergo mutarotation, meaning it interconverts between α and β anomers in aqueous solution.
• β-form of glucose is obtained by crystallisation from concentrated solution of glucose: True. On crystallization from concentrated solution, β-D-glucose is formed.

The true statement related to the given context is:

Its pentaacetate does not react with \( NH_2OH \)

Correct Answer: (D)