Question

Write chemical reactions to show that open structure of D-glucose contains the following :
(i) Straight chain
(ii) Five alcohol groups
(iii) Aldehyde as carbonyl group

Answer 1

(i) Glucose when heated with HI it gives n-hexane which suggests that all the carbons are forming straight chain structure in glucose.

(ii) When glucose is made to react with acetic anhydride it gives glucose pentaacetate which confirms the presence of five OH group in glucose.

(iii) When glucose is treated with mild oxidizing agent it will form six carbon carboxylic acid hence the carbonyle group is present as an aldehyde.