question_answer 76)

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

Answer:

                  Sucrose is dextrorotatory, with a specific rotation of  but on hydrolysis, it gives eauimolar  amounts of glucose which is dextrorotatory and fructose which is laevorotatory. Since the laevorotatin ,S-I fructose (- 92-4°) is much more than dextrorotadon of glucose (+ 52-5°), therefore, the resulting solution  becomes laevorotatory.