Lesson eLearning

Which monosaccharide gives a positive Benedict’s test (brick‑red precipitate) at neutral pH?

easy MCQ 1 mark Class 12 · Chemistry · Biomolecules
  1. glucose
  2. sucrose
  3. lactose
  4. fructose
Answer
glucose

The correct answer is glucose — Therefore the correct answer is glucose.

Step-by-step solution

  1. Identify reducing sugars; Benedict’s reagent reacts with aldehyde or keto groups that can reduce Cu²⁺.
  2. Determine which of the options can act as reducing sugars: glucose, sucrose, lactose, fructose.
  3. Glucose has a free aldehyde group at the anomeric carbon and is a reducing sugar.
  4. Thus glucose gives a positive test.
  5. Therefore the correct answer is glucose.
Common mistake: Confusing sucrose and lactose as reducing sugars

Concept tested: Reducing sugars in Benedict’s test

Published · How this solution was prepared and checked

← All Biomolecules questions