Question

Which of the following statement(s) is/are true about the carbohydrates?

• A. Glucose and lactose reduce Fehlings solution due to presence of aldehyde group
• B. Fructose reduces Fehlings solution due to presence of alpha hydroxy ketone
• C. Sucrose and fructose are non-reducing sugar
• D. All monosaccharides, whether ketose or aldose are reducing sugars

Answer 1

Answer: (A), (B), (D)

All monosaccharides, whether ketose or aldose are reducing sugars

Carbohydrates that reduce the Fehling’s solution and
Tollens’ reagent are reducing sugars.
Examples : Fructose, glucose, maltose, lactose etc.

All monosaccharides, whether ketose or aldose are reducing sugars.

Aldehyde group in glucose and lactose reduces the Fehling's solution and tollen's reagent.
Alpha hydroxy keto group in fructose will reduce the Fehling's solution and tollen's reagent.
Sucrose is a non-reducing sugar.
Hence, statements (a), (b) and (c) are correct.