Assertion (A): Glucose gets oxidized to six carbon gluconic acid on reaction with bromine water.
Reason (R): The carbonyl group is absent in the open chain structure of glucose.
Reason (R): The carbonyl group is absent in the open chain structure of glucose.
Show Hint
- Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of the Assertion (A).
- Both Assertion (A) and Reason (R) are true, but Reason (R) is not the correct explanation of the Assertion (A).
- Assertion (A) is true, but Reason (R) is false.
- Assertion (A) is false, but Reason (R) is true.
The Correct Option is C
Solution and Explanation
Chemical properties and structural elucidation of D-glucose.
Step 2: Meaning
Mild oxidizing agents test for the presence of specific functional groups, such as aldehydes.
Step 3: Analysis
Bromine water is a mild oxidizing agent. When glucose is treated with bromine water, it is oxidized to gluconic acid, demonstrating the presence of an aldehyde group in its open-chain structure.
• Bromine water is a mild oxidizing agent that selectively oxidizes aldehydes without affecting primary alcohol groups.
• D-Glucose exists in equilibrium between cyclic forms and a small amount of the open-chain form.
• The open-chain structure contains a free aldehyde group at the C1 position: \[ -CHO. \]
• Bromine water oxidizes this aldehyde group into a carboxylic acid: \[ -CHO \longrightarrow -COOH. \]
• Consequently, glucose is converted into: \[ \boxed{\text{Gluconic acid}.} \]
• This reaction demonstrates that glucose behaves as a reducing sugar.
• The oxidation occurs only because the open-chain form contains a free aldehyde group that is available for oxidation.
• Therefore, the successful oxidation of glucose by bromine water provides important experimental evidence for the presence of an aldehyde group in the open-chain structure of glucose.
• Hence, both the Assertion and the Reason are true, and the Reason correctly explains the Assertion.
Step 4: Conclusion
The Reason states that the carbonyl group is absent, which is a completely false chemical statement.
Final Answer: (C)
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