Chemistry - ALCOHOL & ETHER Question with Solution | TestHub

The reaction of glucose with HCN adds a carbon atom, which becomes a chiral center. Glucose has 4 chiral carbons. The addition of HCN to glucose converts the aldehyde group to a cyanohydrin, creating a new chiral carbon. Therefore, the product has 5 chiral carbons.

The structure of glucose is: $CHO-(CHOH{)}_4-C{H}_{2}OH$. After reaction with HCN, the product is $CH(CN)OH-(CHOH{)}_4-C{H}_{2}OH$. The original glucose molecule had 4 chiral carbons. The carbon of the aldehyde group is now bonded to four different groups (H, CN, OH, and the rest of the molecule), making it a chiral carbon as well. Thus, the product has 5 chiral carbons.