Question

What is the action of following reagents on glucose?
1. Bromine water
2. Hydroxylamine

Answer 1

1. Action of bromine water on glucose:
The oxidation of glucose wirh bromine water (which is a mild oxidizing agent) gives gluconic acid. This indicates the presence of aldehyde group.
\[\begin{array}{cc}
\phantom{.........}\ce{CHO}\phantom{......................}\ce{COOH}\phantom{.............}\\
\phantom{}|\phantom{............................}|\phantom{......}\\
\ce{(CHOH)4 + [O] ->[Bromine water] (CHOH)4}\\
\phantom{.........}|\phantom{.............................}|\phantom{...............}\\
\phantom{...............}\ce{\underset{\text{Glucose}}{CH2OH}}\phantom{.......................}\ce{\underset{\text{Gluconic acid}}{CH2OH}}\phantom{...............}
\end{array}\]

2. Action of hydroxylamine on glucose:
The reaction of glucose with hydroxylamine gives glucoxime. This indicates the presence of carbonyl group.
\[\begin{array}{cc}
\phantom{....................}\ce{CHO}\phantom{.........................}\ce{CH = N - OH }\phantom{.............}\\
\phantom{...}|\phantom{............................}|\phantom{......}\\
\ce{(CHOH)4 ->[NH2-OH] (CHOH)4 + H2O}\\
\phantom{.............}|\phantom{.............................}|\phantom{...............}\\
\phantom{................}\ce{\underset{\text{Glucose}}{CH2OH}}\phantom{....................}\ce{\underset{\text{Glucoxime}}{CH2OH}}\phantom{...............}
\end{array}\]