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Monosaccharides are polyhydric aldehydes...

Monosaccharides are polyhydric aldehydes and ketones which cannot be hydrolysed into simpler carbohydrates. The monosaccharides containing `-CHO` group are called aldoses while those containing `C=O` group are called ketoses. The aldehyde group is always present at `C_(1)` while keto group is generally present at `C_(2)`. All monosaccharides are oxidised by Tollen's reagent and Fehling solution and are called reducing sugars.
The monosaccharide molecules may be assigned D and L-configurations depending upon whether the configuration of the molecule is related to D- or L-glyceraldehyde. If the `-OH` group is attached to the carbon adjacent to the `-CH_(2)OH` group (last chiral carbon) is on the right hand side, it is assigned D-configuration. The molecule is assigned L-configuration if the -OH group attached to the carbon adjacent to the `-CH_(2)OH` group is on the left. The monosaccharides contain one or more chiral carbon atoms. Pentoses and hexoses have cyclic structures furanose (five membered) and pyranose (six membered). During cyclization, `C_(1)` in aldohexoses and `C_(2)` in fructose become chiral and the newly formed -OH group may be either on the left or on the right in Fischer projection formulae. These monosaccharides, therefore, exist in two stereoisomeric forms called `alpha`-anomer and `beta`-anomer while `C_(1) and C_(2)` are called glycosidic or anomeric carbon. The bonds joining glycosidic carbon are called glycosidic linkages. `D(+)` glucose exists in two stereoisomeric forms, `alpha`-D- glucose and `beta`-D-glucose. When either of these two forms of glucose i.e., `alpha-D-`glucose are dissolved in water and allowed to stand, these get slowly converted into other form and an equilibrium mixture of both is formed. This process is called mutarotation.
Mutarotation does not occur in

A

sucrose

B

D-glucose

C

L-glucose

D

none of these.

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To solve the question regarding the phenomenon of mutarotation and identify in which sugar it does not occur, we can follow these steps: ### Step-by-Step Solution: 1. **Understanding Mutarotation**: - Mutarotation is the change in the optical rotation of a sugar solution as it equilibrates between its anomeric forms (alpha and beta). This process occurs in sugars that can exist in these two forms. 2. **Identifying the Sugars**: - We have the following options: - Option 1: Sucrose - Option 2: Glucose - Option 3: D-Glucose - Option 4: L-Glucose 3. **Analyzing Each Option**: - **Glucose**: Glucose can exist in both alpha and beta forms. Therefore, it undergoes mutarotation. - **D-Glucose**: This is simply the D-form of glucose, which also can exist in alpha and beta forms, thus it undergoes mutarotation. - **L-Glucose**: Similar to D-glucose, L-glucose can also exist in anomeric forms and undergoes mutarotation. - **Sucrose**: Sucrose is a disaccharide composed of glucose and fructose. It does not have anomeric forms like monosaccharides do. When sucrose is hydrolyzed, it produces glucose and fructose, which can undergo mutarotation. However, sucrose itself does not exhibit mutarotation. 4. **Conclusion**: - The sugar that does not undergo mutarotation is **sucrose**. ### Final Answer: Mutarotation does not occur in **sucrose**. ---
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Monosaccharides are polyhydric aldehydes and ketones which cannot be hydrolysed into simpler carbohydrates. The monosaccharides containing -CHO group are called aldoses while those containing C=O group are called ketoses. The aldehyde group is always present at C_(1) while keto group is generally present at C_(2) . All monosaccharides are oxidised by Tollen's reagent and Fehling solution and are called reducing sugars. The monosaccharide molecules may be assigned D and L-configurations depending upon whether the configuration of the molecule is related to D- or L-glyceraldehyde. If the -OH group is attached to the carbon adjacent to the -CH_(2)OH group (last chiral carbon) is on the right hand side, it is assigned D-configuration. The molecule is assigned L-configuration if the -OH group attached to the carbon adjacent to the -CH_(2)OH group is on the left. The monosaccharides contain one or more chiral carbon atoms. Pentoses and hexoses have cyclic structures furanose (five membered) and pyranose (six membered). During cyclization, C_(1) in aldohexoses and C_(2) in fructose become chiral and the newly formed -OH group may be either on the left or on the right in Fischer projection formulae. These monosaccharides, therefore, exist in two stereoisomeric forms called alpha -anomer and beta -anomer while C_(1) and C_(2) are called glycosidic or anomeric carbon. The bonds joining glycosidic carbon are called glycosidic linkages. D(+) glucose exists in two stereoisomeric forms, alpha -D- glucose and beta -D-glucose. When either of these two forms of glucose i.e., alpha-D- glucose are dissolved in water and allowed to stand, these get slowly converted into other form and an equilibrium mixture of both is formed. This process is called mutarotation. Two forms of D-glucopyranose are called

Monosaccharides are polyhydric aldehydes and ketones which cannot be hydrolysed into simpler carbohydrates. The monosaccharides containing -CHO group are called aldoses while those containing C=O group are called ketoses. The aldehyde group is always present at C_(1) while keto group is generally present at C_(2) . All monosaccharides are oxidised by Tollen's reagent and Fehling solution and are called reducing sugars. The monosaccharide molecules may be assigned D and L-configurations depending upon whether the configuration of the molecule is related to D- or L-glyceraldehyde. If the -OH group is attached to the carbon adjacent to the -CH_(2)OH group (last chiral carbon) is on the right hand side, it is assigned D-configuration. The molecule is assigned L-configuration if the -OH group attached to the carbon adjacent to the -CH_(2)OH group is on the left. The monosaccharides contain one or more chiral carbon atoms. Pentoses and hexoses have cyclic structures furanose (five membered) and pyranose (six membered). During cyclization, C_(1) in aldohexoses and C_(2) in fructose become chiral and the newly formed -OH group may be either on the left or on the right in Fischer projection formulae. These monosaccharides, therefore, exist in two stereoisomeric forms called alpha -anomer and beta -anomer while C_(1) and C_(2) are called glycosidic or anomeric carbon. The bonds joining glycosidic carbon are called glycosidic linkages. D(+) glucose exists in two stereoisomeric forms, alpha -D- glucose and beta -D-glucose. When either of these two forms of glucose i.e., alpha-D- glucose are dissolved in water and allowed to stand, these get slowly converted into other form and an equilibrium mixture of both is formed. This process is called mutarotation. Which of the following statements is not correct?

Monosaccharides are polyhydric aldehydes and ketones which cannot be hydrolysed into simpler carbohydrates. The monosaccharides containing -CHO group are called aldoses while those containing C=O group are called ketoses. The aldehyde group is always present at C_(1) while keto group is generally present at C_(2) . All monosaccharides are oxidised by Tollen's reagent and Fehling solution and are called reducing sugars. The monosaccharide molecules may be assigned D and L-configurations depending upon whether the configuration of the molecule is related to D- or L-glyceraldehyde. If the -OH group is attached to the carbon adjacent to the -CH_(2)OH group (last chiral carbon) is on the right hand side, it is assigned D-configuration. The molecule is assigned L-configuration if the -OH group attached to the carbon adjacent to the -CH_(2)OH group is on the left. The monosaccharides contain one or more chiral carbon atoms. Pentoses and hexoses have cyclic structures furanose (five membered) and pyranose (six membered). During cyclization, C_(1) in aldohexoses and C_(2) in fructose become chiral and the newly formed -OH group may be either on the left or on the right in Fischer projection formulae. These monosaccharides, therefore, exist in two stereoisomeric forms called alpha -anomer and beta -anomer while C_(1) and C_(2) are called glycosidic or anomeric carbon. The bonds joining glycosidic carbon are called glycosidic linkages. D(+) glucose exists in two stereoisomeric forms, alpha -D- glucose and beta -D-glucose. When either of these two forms of glucose i.e., alpha-D- glucose are dissolved in water and allowed to stand, these get slowly converted into other form and an equilibrium mixture of both is formed. This process is called mutarotation. Which of the following pairs give positive Tollen's test?

Monosaccharides are polyhydric aldehydes and ketones which cannot be hydrolysed into simpler carbohydrates. The monosaccharides containing -CHO group are called aldoses while those containing C=O group are called ketoses. The aldehyde group is always present at C_(1) while keto group is generally present at C_(2) . All monosaccharides are oxidised by Tollen's reagent and Fehling solution and are called reducing sugars. The monosaccharide molecules may be assigned D and L-configurations depending upon whether the configuration of the molecule is related to D- or L-glyceraldehyde. If the -OH group is attached to the carbon adjacent to the -CH_(2)OH group (last chiral carbon) is on the right hand side, it is assigned D-configuration. The molecule is assigned L-configuration if the -OH group attached to the carbon adjacent to the -CH_(2)OH group is on the left. The monosaccharides contain one or more chiral carbon atoms. Pentoses and hexoses have cyclic structures furanose (five membered) and pyranose (six membered). During cyclization, C_(1) in aldohexoses and C_(2) in fructose become chiral and the newly formed -OH group may be either on the left or on the right in Fischer projection formulae. These monosaccharides, therefore, exist in two stereoisomeric forms called alpha -anomer and beta -anomer while C_(1) and C_(2) are called glycosidic or anomeric carbon. The bonds joining glycosidic carbon are called glycosidic linkages. D(+) glucose exists in two stereoisomeric forms, alpha -D- glucose and beta -D-glucose. When either of these two forms of glucose i.e., alpha-D- glucose are dissolved in water and allowed to stand, these get slowly converted into other form and an equilibrium mixture of both is formed. This process is called mutarotation. The maximum number of optical isomers of glucose expected are

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If monosaccharide contains an aldehyde group it is known As

The polymer formed with same monosaccharide is called as