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

Explanation

Glucose reacts with hydroxylamine `(NH_2OH)` to form a monoxime and adds one molecuole of hydrogen cyanide (HCN) to give a cyanohydrin. Therefore, glucose contains a carbonyl group which can be either an aldehyde or a ketone. On mild oxidation with `Br_(2)-H_(2)O`, glucose gives a carboxylic acid , i.e, gluconic acid containing the same carbon atoms as present in glucose. This indicates that the carbonyl group presnet in glucose is an aldehydic group and not a ketonic group. For structure of oxime , cyanohydrin and gluconic acid.