The carbohydrates in which the following properties are found are called reducing sugars. The reduction of Tollen’s reagent, Fehling’s solution, Benedict’s solution. All monosaccharides are reducing sugars. Contrary to this the carbohydrates in which the above properties are not found are called non-reducing sugars. For example, sucrose, starch, cellulose, etc. The disaccharides, in which carbonyl group of any one monosaccharide from both the monosaccharides, is present as hemiacetal or ketal and does not involve in glycosidic linkage formation, are reducing. For example, maltose and lactose. Two diastereomeric monosaccharides are called epimers when their configuration differs only at stereogenic centre. Monosaccharides form glycoside with alcohol in the presence of an acid. All monosaccharides show mutarotation.

Which one of the following is C-2 epimers?

Glucose and mannose

The correct answer is option 2. Glucose and mannose.

Epimers are diastereomers that differ in configuration at only one stereocenter. The term epimer comes from the Greek word epi, which means "above" or "on top of". This is because epimers are similar to each other, but they differ in configuration at one particular point.

For example, glucose and mannose are epimers because they differ in configuration at the C-2 carbon. The hydroxyl group on glucose is in the alpha configuration, while the hydroxyl group