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 HCN and with HI [C] Reaction with HNO ₃ and with Acetic anhydride [D] Reaction with aqueous Bromine and with Hydroxylamine

Step-by-step solution

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 ( NaHSO₃ ). All other reactions (with HCN , HI , HNO₃ , acetic anhydride, aqueous bromine, hydroxylamine) do occur successfully. The two tests not answered by glucose correspond to option [A].