Assertion : The specific rotation of a freshly prepared solution of `alpha`-glucose decreases from + `112^(@)` to `52.7^(@)` while that of `beta` glucose increases from `+19^(@)` to `52.7^(@)` .
Reason: The change in specific rotation of an optically active compound with time to an equilibrium value is called mutarotation.
Assertion : The specific rotation of a freshly prepared solution of `alpha`-glucose decreases from + `112^(@)` to `52.7^(@)` while that of `beta` glucose increases from `+19^(@)` to `52.7^(@)` .
Reason: The change in specific rotation of an optically active compound with time to an equilibrium value is called mutarotation.
Reason: The change in specific rotation of an optically active compound with time to an equilibrium value is called mutarotation.
A
If both assertion and reason are true and the reason is the correct explanation of the assertion.
B
If both assertion and reason are true but reason is not the correct explanation of the assertion.
C
If assertion is true but reason is false
D
if the assertion and reason both are false
Text Solution
AI Generated Solution
The correct Answer is:
To solve the question, we need to analyze both the assertion and the reason provided.
### Step 1: Understand the Assertion
The assertion states that the specific rotation of freshly prepared solutions of alpha-glucose decreases from +112° to 52.7°, while that of beta-glucose increases from +19° to 52.7°.
- **Alpha-glucose**: Initially has a specific rotation of +112°. Over time, it decreases to +52.7°.
- **Beta-glucose**: Initially has a specific rotation of +19°. Over time, it increases to +52.7°.
This indicates that both forms of glucose are interconverting in solution, leading to a change in their specific rotations.
### Step 2: Understand the Reason
The reason states that the change in specific rotation of an optically active compound with time to an equilibrium value is called mutarotation.
- **Mutarotation**: This is a phenomenon observed in sugars where the optical rotation changes over time as the anomeric forms (alpha and beta) interconvert until an equilibrium is reached.
### Step 3: Analyze the Relationship
Now, we need to determine if the reason correctly explains the assertion.
- The assertion is true because it accurately describes the behavior of alpha and beta glucose in solution.
- The reason is also true as it defines mutarotation correctly.
However, while the reason explains what mutarotation is, it does not specifically explain why the specific rotations of alpha and beta glucose change in the manner described in the assertion.
### Conclusion
Both the assertion and the reason are true, but the reason does not serve as a correct explanation for the assertion. Therefore, the correct conclusion is that both statements are true, but the reason is not the correct explanation of the assertion.
### Final Answer
Both assertion and reason are true, but the reason is not the correct explanation of the assertion.
---
To solve the question, we need to analyze both the assertion and the reason provided.
### Step 1: Understand the Assertion
The assertion states that the specific rotation of freshly prepared solutions of alpha-glucose decreases from +112° to 52.7°, while that of beta-glucose increases from +19° to 52.7°.
- **Alpha-glucose**: Initially has a specific rotation of +112°. Over time, it decreases to +52.7°.
- **Beta-glucose**: Initially has a specific rotation of +19°. Over time, it increases to +52.7°.
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