Despite formally containing a ketonic functional group rather than an aldehydic group, which of the — Biomolecules Chemistry Question

💡 Solution & Explanation

D-Fructose is formally a ketohexose. Generally, simple ketones fail to reduce weak oxidants like Fehling's solution. However, strictly under the strongly alkaline conditions mandated by Fehling's testing, fructose rapidly isomerizes directly into highly reducing aldoses (glucose and mannose) via enediol intermediates, yielding a positive test.