This chemistry question involves key chemical concepts and calculations. The detailed solution below walks through each step, from identifying the reaction type to computing the final answer.
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Here are the answers to the questions: 2. (i) Epimers Epimers are stereoisomers that differ in configuration at only one chiral carbon atom (excluding the anomeric carbon in cyclic sugars). They are a type of diastereomer. Examples: • D-Glucose and D-Galactose are C-4 epimers. • D-Glucose and D-Mannose are C-2 epimers. • D-Xylose and D-Lyxose are C-2 epimers. 2. (ii) Kiliani-Fischer synthesis The Kiliani-Fischer synthesis is a method used to lengthen the carbon chain of an aldose by one carbon atom, thereby converting an aldose into a new aldose with one more carbon. The process involves two main steps: 1. Reaction of the aldose with hydrogen cyanide (HCN) to form a pair of cyanohydrins. This step creates a new chiral center. 2. Hydrolysis of the cyanohydrins to form aldonic acids, followed by reduction (e.g., with hydrogen and a catalyst) to yield two new epimeric aldoses. This synthesis is important for synthesizing higher sugars from lower ones. 2. (iii) Storage polysaccharides Storage polysaccharides are complex carbohydrates that serve as a form of energy storage in living organisms. They are typically large polymers of monosaccharide units linked by glycosidic bonds. Examples: • Starch: The primary energy storage polysaccharide in plants. It is a mixture of amylose (linear) and amylopectin (branched) glucose polymers. • Glycogen: The main energy storage polysaccharide in animals and fungi. It is a highly branched polymer of glucose units, primarily stored in the liver and muscles. 2. (iv) Enantiomers Enantiomers are stereoisomers that are non-superimposable mirror images of each other. They possess identical physical properties (e.g., melting point, boiling point, solubility) in an achiral environment but differ in their interaction with plane-polarized light (rotating it in opposite directions) and in their reactions with other chiral molecules. Each chiral molecule has one enantiomer. Example: D-glucose and L-glucose are enantiomers.