Question

Fructose reduces tollens reagent due to______

• A. Primary alcoholic group
• B. Secondary alcoholic group
• C. Enolization of fructose followed by conversation to aldehyde by base
• D. Asymmetric carbon atoms

Answer 1

Answer: (C)

Tollen's reagent is $\left(AgN{O}_3+N{H}_{4}OH\right)$ and it enables basic medium. Fructose is a keto-hexose, still it can reduce Tollen's reagent. Because in basic medium, it undergoes epimerisation (Lobry de-Bruyn Van Ekenstein rerrangement) to give an aldehyde (D-glucose/D-mannose).

Throughout the equilibrium, keto-enol tautomeism takes place.