Glucose does not give reaction with which of the following? |
\(NH_2-OH\) \(HCN\) \((CH_3CO)_2O\) \(NaHSO_3\) |
\(NaHSO_3\) |
The correct answer is option 4. \(NaHSO_3\). Let us explore why glucose does not react with sodium bisulfite (\(NaHSO_3\)) but reacts with the other reagents mentioned: 1. Reaction with Hydroxylamine (\(NH_2-OH\)): Hydroxylamine reacts with the aldehyde group of glucose to form an oxime. In the case of glucose, which contains an aldehyde group in its open-chain form, hydroxylamine forms a glucose oxime. This reaction is used to test for the presence of aldehyde or ketone groups in carbohydrates. The aldehyde group reacts with hydroxylamine to form a stable oxime, which indicates a positive reaction. 2. Reaction with Hydrogen Cyanide (\(HCN\)): Hydrogen cyanide reacts with the aldehyde group of glucose to form a cyanohydrin. In this reaction, the aldehyde group of glucose is converted into a cyanohydrin. This reaction is important in carbohydrate chemistry for determining the presence of aldehyde groups and for further derivatization of sugars. The resulting cyanohydrin can be used for further chemical reactions. 3. Reaction with Acetic Anhydride (\((CH_3CO)_2O\)): Acetic anhydride reacts with the hydroxyl groups of glucose to form glucose pentaacetate. This is an esterification reaction where each hydroxyl group in glucose reacts with acetic anhydride. This reaction is used in the preparation of glucose derivatives for structural studies and identification. The esterification of all hydroxyl groups in glucose yields a compound where the hydroxyl groups are replaced by acetate groups. 4. Reaction with Sodium Bisulfite (\(NaHSO_3\)): Sodium bisulfite reacts with free aldehyde or ketone groups to form bisulfite addition compounds. In the case of glucose, the aldehyde group in the open-chain form would normally react with sodium bisulfite. However, in aqueous solution, glucose predominantly exists in its cyclic form (as a hemiacetal) rather than in the open-chain form with a free aldehyde group. The cyclic form of glucose does not have a free aldehyde group available for reaction with sodium bisulfite. Therefore, glucose does not react with sodium bisulfite under typical conditions because the aldehyde group is involved in forming the ring structure and is not available for the bisulfite addition. Summary: Hydroxylamine (\(NH_2-OH\)): Reacts with the aldehyde group to form an oxime. Hydrogen Cyanide (\(HCN\)): Reacts with the aldehyde group to form a cyanohydrin. Acetic Anhydride (\((CH_3CO)_2O\)): Reacts with hydroxyl groups to form glucose pentaacetate. Sodium Bisulfite (\(NaHSO_3\)): Does not react with glucose in its cyclic form, as the aldehyde group is not available for this reaction. |