Given below are two statements:
Statement I: D-(+)-glucose + D-(+) fructose →(-H₂ O) Sucrose
sucrose →(hydrolysis) D-(+) glucose +D-(+) fructose
Statement II: Invert sugar is formed during sucrose hydrolysis
In the light of the above statements, choose the correct answer from the options given below

Solution

Chemistry ma’am · 4 steps

Watch the sign in brackets: fructose is D-(−), not D-(+), and that alone makes Statement I false.

1. D versus sign. The letter D tells you the configuration at the lowest chiral carbon. The sign in brackets tells you which way the sugar rotates plane-polarised light. These two are independent, so a D sugar can be (+) or (−).
2. Check Statement I. Sucrose is made from α-D-glucose and β-D-fructose. Glucose is dextrorotatory, D-(+), but fructose is laevorotatory, D-(−). Writing D-(+)-fructose is wrong, so Statement I is false.

   Sugar	Specific rotation	Direction
   Sucrose	+66.5°	dextro (+)
   D-glucose	+52.5°	dextro (+)
   D-fructose	-92.4°	laevo (−)
   Hydrolysis mixture	net negative	laevo (−)

3. Check Statement II. Hydrolysis gives equal amounts of glucose and fructose, and fructose rotates more strongly to the left than glucose rotates to the right. So the sign flips from (+) to (−), and this laevorotatory mixture is called invert sugar. Statement II is true.
4. So. Statement I is false and Statement II is true, which is option (b).

The idea to keep. The D/L label and the (+)/(−) sign are two separate facts. Remember glucose is D-(+) and fructose is D-(−); that sign difference is exactly why sucrose hydrolysis gives invert sugar.

Answer from the NTA final answer key. Solution by PrepWiser.