Question

Statement–I: Glucose is in pyranose form and has free anomeric hydroxyl group. Statement–II: In sucrose, glucose is in pyranose form and fructose is in furanose form.

• A. Both I and II are true
• B. I is true, but II is false
• C. I is false, but II is true
• D. Both I and II are false

Hint:

Free glucose → pyranose form with free anomeric carbon
Sucrose → non-reducing sugar (both anomeric carbons involved in glycosidic bond) Always identify ring size and anomeric carbon in carbohydrate questions.

Answer 1

The Correct Option is A

Step 1: Analyse Statement–I. In aqueous solution, glucose predominantly exists in the pyranose (six-membered ring) form. In free glucose, the anomeric carbon (C-1) contains a free hydroxyl (\(-OH\)) group, which is responsible for its reducing nature. \[ \Rightarrow \text{Statement–I is true.} \]
Step 2: Analyse Statement–II. Sucrose is a disaccharide formed by: \[ \alpha\text{-D-glucopyranose} + \beta\text{-D-fructofuranose} \] Thus:
Glucose unit is in pyranose form
Fructose unit is in furanose form \[ \Rightarrow \text{Statement–II is also true.} \]
Step 3: Conclude. Since both statements are correct: \[ \boxed{\text{Both Statement–I and Statement–II are true}} \]