Question

Which of the following statement(s) are incorrect?

• A. All oligosaccharides give same monosaccharide on acidic hydrolysis.
• B. All monosaccharides are reducing sugar.
• C. Starch and cellulose are long chain polymer high molecular mass.
• D. Open chain glucose and cyclic \( \alpha \) and \( \beta \)-D-glucose are in equilibrium in aqueous solution.

Answer 1

The Correct Option is A

Step 1: Statement (A).
The statement "All oligosaccharides give the same monosaccharide on acidic hydrolysis" is incorrect. The products of acidic hydrolysis of oligosaccharides depend on the types of monosaccharides present in the oligosaccharide. Oligosaccharides with different monosaccharide units will yield different monosaccharides upon hydrolysis.
Step 2: Statement (B).
The statement "All monosaccharides are reducing sugars" is correct. Monosaccharides, such as glucose, fructose, etc., have free aldehyde or ketone groups, making them reducing sugars that can reduce Benedict’s or Fehling’s solution.
Step 3: Statement (C).
The statement "Starch and cellulose are long chain polymers with high molecular mass" is correct. Both starch and cellulose are polysaccharides with large molecular masses, consisting of long chains of glucose units.
Step 4: Statement (D).
The statement "Open chain glucose and cyclic \( \alpha \) and \( \beta \)-D-glucose are in equilibrium in aqueous solution" is correct. In an aqueous solution, D-glucose exists in equilibrium between its open-chain form and two cyclic anomeric forms (\( \alpha \)- and \( \beta \)-D-glucose).
Step 5: Conclusion.
Statement (A) is incorrect, so the correct answer is (A). Final Answer: (A)