Question:medium
The correct statement(s) regarding sugars is(are):
Given: Specific rotations of L-(-)-glucose and L-(+)-fructose are \(-52.5^\circ\) and \(+92.5^\circ\), respectively.
The correct statement(s) regarding sugars is(are):
Given: Specific rotations of L-(-)-glucose and L-(+)-fructose are \(-52.5^\circ\) and \(+92.5^\circ\), respectively.
Given: Specific rotations of L-(-)-glucose and L-(+)-fructose are \(-52.5^\circ\) and \(+92.5^\circ\), respectively.
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Remember the unique properties of monosaccharides and disaccharides:
- Reducing sugars: Have a free aldehyde or ketone group (or can isomerize to one).
- Keto-enol tautomerism: Allows ketoses like fructose to give positive Tollen's/Fehling's tests.
- Invert sugar: An equimolar mixture of D-glucose and D-fructose formed from sucrose hydrolysis, named for the change in optical rotation.
- Reducing sugars: Have a free aldehyde or ketone group (or can isomerize to one).
- Keto-enol tautomerism: Allows ketoses like fructose to give positive Tollen's/Fehling's tests.
- Invert sugar: An equimolar mixture of D-glucose and D-fructose formed from sucrose hydrolysis, named for the change in optical rotation.
Updated On: May 20, 2026
- On treatment with HNO$_3$, gluconic acid is oxidized to saccharic acid, whereas glucose is not oxidized to saccharic acid.
- Fructose gives a positive Fehling's test because it isomerises to glucose and another aldohexose in the presence of Fehling's reagent.
- Invert sugar is an equimolar mixture of D-glucose and D-fructose formed after hydrolysis of the corresponding disaccharide.
- Specific rotation of invert sugar is $-40^{\circ}$.
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The Correct Option is B
Solution and Explanation
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