Question

Given below are two statements :
Statement I : Maltose is a non-reducing sugar
Statement II : Lactose is a reducing sugar

• A. Both statement I and statement II are correct
• B. Statement I is correct but statement II is incorrect
• C. Statement I is incorrect but statement II is correct
• D. Both statement I and statement II are incorrect

Hint:

Among common disaccharides, \textbf{Sucrose} is the only non-reducing sugar because both anomeric carbons (C1 of glucose and C2 of fructose) are involved in the glycosidic bond.
Maltose and Lactose are always reducing.

Answer 1

The Correct Option is C

To analyze the given statements regarding sugars, let's examine each statement based on fundamental chemistry concepts pertaining to sugars:

• Statement I: Maltose is a non-reducing sugar — This statement is incorrect. Maltose is a reducing sugar. It consists of two glucose units linked together. The structure of maltose has a free aldehyde group, which allows it to act as a reducing agent. Therefore, maltose can reduce other compounds and itself get oxidized, exhibiting characteristics of a reducing sugar.
• Statement II: Lactose is a reducing sugar — This statement is correct. Lactose consists of one glucose unit and one galactose unit. It contains a free aldehyde group at the end of the sugar molecule chain, allowing it to reduce other compounds. Thus, lactose is indeed a reducing sugar.

Based on the examination of both statements:

• Statement I is incorrect because maltose is a reducing sugar.
• Statement II is correct because lactose is a reducing sugar.

Hence, the correct option is: Statement I is incorrect but statement II is correct.