Question

Select the correct statements : (a) Glucose has 2 anomeric forms.
(b) Both forms have difference in configuration at \(C_1\) carbon.
(c) \(\alpha\)-form has more melting point than \(\beta\)-form.
(d) Specific rotation of \(\alpha\)-form is \(+19^\circ\) and \(\beta\)-form has \(+112^\circ\).
(e) \(\alpha\)-form crystallises at \(307^\circ\) and \(\beta\)-form crystallises at \(371^\circ\).

• A. b, c is correct
• B. a, b and e is correct
• C. a, b is correct
• D. a, b, d, e is correct

Answer 1

The Correct Option is D

Concept:
Glucose exhibits mutarotation due to the presence of two cyclic forms called anomers. These are \(\alpha\)-D-glucose and \(\beta\)-D-glucose, which differ in configuration at the anomeric carbon (\(C_1\)). Step 1: Analyze statement (a). Glucose has two anomeric forms: \[ \alpha\text{-D-glucose} \quad \text{and} \quad \beta\text{-D-glucose} \] Thus, (a) is correct. Step 2: Analyze statement (b). The difference between these forms occurs at the anomeric carbon \(C_1\). Thus, (b) is correct. Step 3: Analyze statement (c). The \(\beta\)-form actually has higher stability and melting point than the \(\alpha\)-form. Thus, (c) is incorrect. Step 4: Analyze statement (d). Specific rotation values: \[ \alpha\text{-form} = +112^\circ \] \[ \beta\text{-form} = +19^\circ \] Thus, (d) is correct. Step 5: Analyze statement (e). Crystallisation temperatures: \[ \alpha\text{-form} = 307\,K \] \[ \beta\text{-form} = 371\,K \] Thus, (e) is correct. Step 6: Final conclusion. Correct statements: \[ a,\; b,\; d,\; e \] \[ \boxed{\text{Option (4)}} \]