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Sugars: oxidation, Fehling's test, invert sugar and the rotation of a mixture
JEE Advanced 2026
Paper 2 · Question 9
Chemistry
Monosaccharides, reducing sugars and optical rotation
Moderate-Hard
Four benches for four statements: oxidise glucose and gluconic acid with HNO3 and get the same product, run Fehling's on a ketose and watch the copper drop out, hydrolyse sucrose into an equimolar pair, then build the average that turns -40 into -20.
Open the interactive simulationSub-topics covered
- Mild versus strong oxidation of glucose
- Gluconic acid and saccharic acid
- Lobry de Bruyn-van Ekenstein rearrangement
- Fehling's test and reducing sugars
- Hydrolysis of sucrose and invert sugar
- Specific rotation of a mixture
- D/L configuration versus (+)/(-) rotation
What it teaches
- A strong oxidant attacks every oxidisable end, not just the reducing one
- Alkali converts a ketose into aldoses through a 1,2-enediol
- A non-reducing disaccharide has both anomeric carbons tied up
- Specific rotation of a mixture is a weighted average, never a sum
- Configuration labels and the measured sign of rotation are independent
Simulation ID
- ADV-2026-P2-CHE-Q09 · revision 1
See this simulation in the library → · open the simulation file on its own