Sucrose is dextrorotatory but the mixture obtained after hydrolysis is laevorotatory. Explain.

Aqueous solution of sucrose is dextrorotatory and rotates plane polarized light entering the solution 66.5° to the right. When sucrose is hydrolysed with dilute acids or invertase enzyme, it gives two products in equimolar concentration, dextrorotatory D-(+)-glucose and laevorotatory D-(-)-fructose. The laevorotation of fructose (–92.4°) is more than dextrorotation of glucose (+ 52.5°), the resulting equimolar mixture of the products is laevorotatory with resulting rotation of -39.9°. Thus, hydrolysis of sucrose brings about a change in the sign of rotation, from dextro (+) to laevo (–). Thus the hydrolysed mixture is laevorotatory.