Sucrose is a dextrorotatory disaccharide.
On hydrolysis, sucrose breaks into an equimolar mixture of:
• D-(+)-glucose (dextrorotatory)
• D-(−)-fructose (laevorotatory)
The magnitude of optical rotation:
| rotation of fructose | > | rotation of glucose |
Since fructose has a much higher laevorotation compared to the dextrorotation of glucose, the net rotation of the mixture becomes laevorotatory.
This hydrolysed solution is called invert sugar.
Statement I:
Sucrose is dextrorotatory, but its hydrolysis product is laevorotatory due to dominance of fructose.
✔ Statement I is true.
Statement II:
The statement wrongly claims that laevorotation of glucose is more than dextrorotation of fructose.
This is incorrect because:
| fructose rotation | > | glucose rotation |
✘ Statement II is false.
Hence, the correct answer is:
Statement I is true but Statement II is false
This concept is very important for JEE Main, JEE Advanced and IIT JEE optical activity questions.
Updated for JEE Main 2026: This PYQ is important for JEE Mains, JEE Advanced and other competitive exams. Practice more questions from this chapter.