Answer to Question #213671 in General Chemistry for rahul

Question

Glucose and Fructose belongs to the carbohydrate family but they react differently, which functional group makes them different from one another and how would you distinguish them by giving simple chemical test?                         

Answer 1

Since fructose has a ketone functional group, the ring closure occurs at carbon # 2. In the case of fructose a five membered ring is formed. The -OH on carbon #5 is converted into the ether linkage to close the ring with carbon #2. This makes a 5 member ring - four carbons and one oxygen.