Identify the 2 chemical tests which is not answered by Glucose having an open chain structure [A] Reaction with Schiff's reagent and with Sodium bisulphite [B] Reaction with $\mathrm{HCN}$ and with $\mathrm{HI}$ [C] Reaction with $\mathrm{HNO}_3$ and with Acetic anhydride [D] Reaction with aqueous Bromine and with Hydroxylamine

Glucose predominantly exists in a cyclic hemiacetal form, so the free aldehyde concentration is extremely low.

Due to this, glucose fails two characteristic aldehyde tests:

It does not restore the pink colour of Schiff's reagent, and it does not form an addition compound with sodium bisulphite ($NaHSO_3$).

All other reactions (with $HCN$, $HI$, $HNO_3$, acetic anhydride, aqueous bromine, hydroxylamine) do occur successfully.

The two tests not answered by glucose correspond to option [A].