Which of the following sugars will not reduce Fehling's reagent?

Sucrose

The correct answer is Option (2) → Sucrose

Fehling's test detects reducing sugars, which have a free aldehyde or a free hemiacetal group.

• Maltose → reducing sugar ✅
• Lactose → reducing sugar ✅
• Fructose → reducing sugar (enolization under alkaline conditions) ✅
• Sucrose → non-reducing sugar (glycosidic linkage blocks the aldehyde/ketone group) ❌