Question

Identify the correct statements.
A. Glucose exists in two anomeric forms.
B. Anomers of glucose differ in configuration at C-1 in cyclic hemiacetal structure.
C. Melting point of \(\alpha\)-anomer of glucose is greater than \(\beta\)-anomer.
D. Specific rotation of \(\alpha\)-anomer is \(+19^\circ\) while for \(\beta\)-anomer is \(+112^\circ\).
E. \(\alpha\) and \(\beta\) anomers of glucose are prepared by crystallization of saturated glucose solution at \(303 \text{ K}\) and \(371 \text{ K}\) respectively.

• A. A and B Only
• B. B and C Only
• C. A, B and D Only
• D. A, B and E Only

Answer 1

The Correct Option is D

Step 1: Understanding the Question:
The question asks to identify correct facts regarding the anomers of D-glucose.
Step 2: Detailed Explanation:
- Statement A: Correct. Glucose exists as \(\alpha\)-D-glucose and \(\beta\)-D-glucose.
- Statement B: Correct. Anomers are diastereomers that differ in configuration only at the hemiacetal carbon (C-1 for glucose).
- Statement C: Incorrect. The melting point of the \(\beta\)-anomer (\(423 \text{ K}\)) is higher than that of the \(\alpha\)-anomer (\(419 \text{ K}\)).
- Statement D: Incorrect. The values are swapped; the \(\alpha\)-anomer has a specific rotation of \(+112^\circ\) and the \(\beta\)-anomer has \(+19^\circ\).
- Statement E: Correct. \(\alpha\)-glucose is obtained by crystallization from concentrated solution of glucose at \(303 \text{ K}\), while \(\beta\)-form is obtained by crystallization from hot and saturated aqueous solution at \(371 \text{ K}\).
Step 3: Final Answer:
Statements A, B, and E are correct.