How will you distinguish `1^(@)` and `2^(@)` hydroxyl groups present in glucose? Explain the reactions.

Explanation

On oxidation with `HNO_(3)`, glucose as well as gluconic acid, both give a dicarboxylic acid, saccharic acid. This indicates the presence of a primary alcoholic `(-OH)` group in glucose. The other `-OH` groups are secondary.
`{:(" "CHO),(" |"),(" "(CHOH)_(4)),(" |"),(" "CH_(2)OH):}+overset(O)rarr underset(" Saccharic acid")({:(" "COOH),(" |"),(" "(CHOH)_(4)),(" |"),(" "COOH):})larrunderset(" Cluconic acid")({:(" "COOH),(" |"),(" "(CHOH)_(4)),(" |"),(" "CH_(2)OH):})`