JEE Challenger
More from Biomolecules
ChemMedMain 2026 • 4th Apr - Shift 1

Evaluation of Statements on Maltose and Lactose Reducing Properties

Given below are two statements:

Statement I: The structure of Maltose is given below:
Maltose is a non-reducing sugar.

Statement II: The structure of Lactose is given below:
Lactose is a reducing sugar.

In the light of the above statements, choose the correct answer from the options given below

Question Diagram 1
Question Diagram 2

Options

A

Both Statement I and Statement II are true

B

Both Statement I and Statement II are false

C

Statement I is true but Statement II is false

D

Statement I is false but Statement II is true

Correct

Topics & Concepts

BiomoleculesCarbohydrates

Step-by-Step Solution

To determine the correctness of the given statements, let us analyze the chemical properties and structures of Maltose and Lactose:

  1. Analysis of Statement I:

    • Maltose is a disaccharide formed by the condensation of two α\alpha-D-glucose molecules linked via an α(1→4)\alpha(1 \rightarrow 4) glycosidic bond.
    • The C-1 (anomeric carbon) of the second glucose unit possesses a free hemiacetal group (−CH(OH)−-\text{CH(OH)}-), which can exist in equilibrium with an open-chain aldehyde form.
    • Because of this free aldehyde group, maltose exhibits mutarotation and reduces Fehling's solution and Tollen's reagent. Therefore, Maltose is a reducing sugar.
    • Thus, Statement I ("Maltose is a non-reducing sugar") is false.

  2. Analysis of Statement II:

    • Lactose is a disaccharide composed of β\beta-D-galactose and β\beta-D-glucose linked by a β(1→4)\beta(1 \rightarrow 4) glycosidic linkage.
    • The C-1 (anomeric carbon) of the glucose unit is free and present as a hemiacetal group.
    • Since it can open to yield a free aldehyde group, lactose easily reduces Fehling's and Tollen's reagents. Therefore, Lactose is a reducing sugar.
    • Thus, Statement II ("Lactose is a reducing sugar") is true.

Conclusion: Statement I is false but Statement II is true.

Correct Option: D

Evaluation of Statements on Maltose and Lactose Reducing Properties | Chemistry PYQ Solution - JEE Challenger