In osazone formation, glucose reacts with three molecules of phenylhydrazine. Which statement is true regarding this ?

Options

A. All the three molecules react in similar fashion
B. Two molecules react in similar manner, while the third reacts in different way
C. All the three molecules react in different ways
D. None of the above is true.

Answer

B

Explanation

First molecule of phenylhydrazine undergoes nucleophilic addition on carbonyl (-CHO in glucose and `gt CO` in fructose) group. Second molecule of the reagent oxidizes -CHOH- at position 2(in aldoses) or `-CH_(2)OH` at position 1 (in ketoses) to from -CHO or `gtC-O` respectivley. The third molecule again undergoes nucleophilic addition on the newly developed carbonyl group to from osazone.