Assertion: A solution of sucrose in water is dextrorotatory but on hydrolysis in the presence of little hydrochloric acid, it becomes laevorotatory.
Reason: Sucrose on hydrolysis gives unequal amounts of glucose and fructose as a result of which change in sign of rotation is observed.
Answer & explanation
Correct answer: option 3
Correct reason: Sucrose on hydrolysis gives equal amounts of glucose and fructose. Since fructose is more laevorotatory than glucose is dextrorotatory, therefore, the sign of rotation changes.