Carbohydrates are classified as monosaccharides, oligosaccharides and polysaccharides depending on their behaviour towards hydrolysis. All monosaccharides containing five or six carbon atoms can have two cyclic structures namely furanose and pyranose form. Oligosaccharides are further classified as di, tri, tetra etc saccharides depeding upon the number of monosaccharide units actually obntained on hyrolysis. In oligosaccharides and polysaccharides, the different monomer units are joined together by glycosidic linkages. The incorrect statement about sucrose is (a) It does not reduce Tollen's reagent for Fehling's solution. (b) It is not optically active. (c) It is an a-D-glucoside. (d) It does not form osazone with phenyl hydrazine.

Step by step solution

01

Understanding Sucrose Structure

Sucrose is a disaccharide composed of one glucose molecule and one fructose molecule joined together via the glycosidic linkage. The glycosidic bond is formed between the C1 (anomeric carbon) of the α-D-glucose and the C2 (also an anomeric carbon) of the β-D-fructose. As a result, it has neither a free aldehyde nor a free ketone group.

02

Analysis of Option A

Option A states that sucrose does not reduce Tollen's reagent or Fehling's solution. Tollen's reagent and Fehling's solution are used to detect the presence of free aldehyde or ketone groups in a carbohydrate. Since sucrose has neither free aldehyde nor ketone groups, this statement is correct.

03

Analysis of Option B

Option B states that sucrose is not optically active. Optical activity is the ability of a molecule to rotate plane-polarized light. Both glucose and fructose are optically active. When they form a sucrose molecule, the odd-order glycosidic bond between them results in an optically active sucrose molecule. Therefore, this statement is incorrect.

04

Analysis of Option C

Option C states that sucrose is an α-D-glucoside. As mentioned in Step 1, sucrose is a disaccharide composed of one α-D-glucose and one β-D-fructose molecule. Hence, this statement is correct.

05

Analysis of Option D

Option D states that sucrose does not form osazone with phenyl hydrazine. Osazone formation is a chemical reaction that occurs when a carbohydrate containing a free aldehyde or ketone group reacts with phenyl hydrazine. As sucrose has neither a free aldehyde nor a ketone group, it will not form osazone with phenyl hydrazine. Thus, this statement is correct. Based on the step-by-step analysis, we can conclude that the incorrect statement about sucrose is: (b) It is not optically active.

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