Question

How do you explain the presence of an aldehydic group in a glucose molecule?

Answer 1

$\text{Reaction which confirms the presence of the carbonyl group in glucose}.$

Glucose reacts with hydroxylamine to form glucoxime and adds a molecule of hydrogen cyanide to give cyanohydrin. These reactions confirm the presence of a carbonyl group $(>C=0)$ in glucose.


$\text{Reaction which confirms the presence of carbonyl group as an aldehydic group in glucose}.$

Glucose gets oxidised to six carbon carboxylic acid (Gluconic acid) on reaction with a mild oxidising agent like bromine water. This indicates that the carbonyl group is present as an aldehydic group.


So, the above discussion confirms the presence of an aldehydic group in glucose.