Non-reducing sugars do not have an OH group attached to the anomeric carbon so they cannot reduce other compounds. All monosaccharides such as glucose are reducing sugars. A disaccharide can be a reducing sugar or a non-reducing sugar. Maltose and lactose are reducing sugars, while sucrose is a non-reducing sugar.

Non-Reducing Sugar: Sucrose

Sucrose is a non-reducing sugar because it does not have a free aldehyde or ketone group in its molecule. When reducing sugars are subjected to a weak oxidizing agent, such as Benedict's reagent, they can be oxidized to produce a colored precipitate. However, this reaction cannot occur with non-reducing sugars.

Explanation:

Reducing sugars are carbohydrates that can donate electrons to another chemical, such as an oxidizing agent. This is due to the presence of a free aldehyde or ketone group in their molecule. These groups can undergo oxidation reactions, which produce a colored precipitate with Benedict's reagent.

Sucrose, on the other hand, is a disaccharide composed of glucose and fructose molecules joined together by a glycosidic bond. This bond prevents the free aldehyde or ketone group from being exposed and makes sucrose a non-reducing sugar. It cannot undergo the oxidation reaction with Benedict's reagent.

Examples of Reducing Sugars:

Maltose and lactose are reducing sugars because they have a free aldehyde or ketone group in their molecules. Glucose is also a reducing sugar.

Conclusion:

Sucrose is a non-reducing sugar, while maltose, lactose, and glucose are reducing sugars. The presence or absence of a free aldehyde or ketone group in their molecules determines whether a sugar is reducing or non-reducing.