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: Understanding the Question:
The question requires identifying the false statement regarding carbohydrates.
Step 2: Detailed Explanation:
1. Oligosaccharides are carbohydrates that yield 2 to 10 monosaccharide units on hydrolysis. They can yield different monosaccharides. For example, sucrose yields glucose and fructose. Thus, Statement 1 is incorrect.
2. All monosaccharides (aldoses and ketoses) possess a free or hemiacetal carbonyl group that can reduce Tollens' or Fehling's reagent. They are all reducing sugars. Statement 2 is correct.
3. Starch and cellulose are polysaccharides made of many glucose units, having high molecular masses. Statement 3 is correct.
4. In aqueous solution, D-glucose exists in an equilibrium between its open-chain form and cyclic $\alpha$ and $\beta$ pyranose forms (mutarotation). Statement 4 is correct.
Step 3: Final Answer:
Statement (1) is incorrect.