QNEET-2024-Ch-27: NEET 2024 Chemistry - Class 12 NEET-2024-Ch-27 Solution: The reagents with which glucose does not react to give the…

Let's analyze each reagent and its reaction with glucose to determine which ones do not react accordingly. Glucose is an aldohexose, meaning it has an aldehyde group in its straight-chain form and can form a cyclic hemiacetal structure. This structure is predominant under physiological conditions. A. Tollen's Reagent: Tollen's reagent is a solution of silver nitrate in ammonia, used to detect reducing sugars. Glucose, having a free aldehyde group or an easily openable hemiacetal in its cyclic form, can reduce Tollen's reagent to metallic silver, showing a positive test. Thus, glucose reacts with Tollen's reagent. B. Schiff's Reagent: Schiff's reagent is used to detect aldehydic groups. It is sensitive to free aldehydes, turning pink when aldehydes are present. Since the aldehyde form of glucose is present in very minute amounts at equilibrium (most glucose is in the cyclic form), it generally does not react strongly with Schiff's reagent, leading to a negative test. C. HCN: Hydrogen cyanide (HCN) can react with carbonyl groups to form cyanohydrins. In the case of glucose, the reactive aldehyde group can react with HCN to form glucosyl cyanohydrin. Thus, glucose does react with HCN. D. NH 2 OH (Hydroxylamine): Hydroxylamine reacts with carbonyl compounds to form oximes. Glucose, containing an aldehyde group, can react with hydroxylamine to form glucose oxime. Therefore, glucose reacts with hydroxylamine. E. NaHSO 3 (Sodium Bisulfite): Sodium bisulfite reacts with aldehydes to form bisulfite adducts. However, because glucose in solution predominantly exists in its cyclic form rather than the open-chain form, it does not readily react with sodium bisulfite. Hence, glucose generally does not react with sodium bisulfite, unless placed under certain conditions that favor the open-chain form. In conclusion, the reagents with which glucose does not react to give the corresponding tests/products are: B. Schiff's Reagent and E. NaHSO 3 Therefore, the correct answer is Option C: B and E .