MHT CET Medical202623 April 2026Morning ShiftChemistryBiomoleculesActual
Why does fructose reduce Fehling's solution?
Options
- ADue to the presence of hydroxy group.
- BDue to the presence of aldehydic group
- CDue to the presence of ketonic group.
- DDue to the presence of alpha-hydroxy ketonic group
Correct answer
D. Due to the presence of alpha-hydroxy ketonic group
Step-by-step solution
Fructose is a monosaccharide containing a ketonic group at the second carbon and hydroxyl groups on adjacent carbons, making it an -hydroxy ketone. Under the alkaline conditions of Fehling's solution, fructose undergoes Lobry de Bruyn-van Ekenstein rearrangement. This rearrangement converts the -hydroxy ketone into an enediol intermediate, which further tautomerizes into an aldose (a mixture of glucose and mannose). The newly formed aldehydic group then readily reduces Fehling's solution. Thus, fructose reduces Feh