Chapter 18, Problem 18.62EP

(a)

Interpretation Introduction

Interpretation: Among the given terms aldoses, ketoses, hexoses and aldohexoses, the term that is applied to both $\text{D}-\text{glucose}$ and $\text{D}-\text{ribose}$ has to be predicted.

Concept introduction: The simplest hydrolyzed form that is obtained from the carbohydrates is known as monosaccharide.  Monosaccharide is categorized into two types.  The first type of monosaccharide is aldoses and the second type of monosaccharide is ketoses.  Aldoses sugar possesses aldehyde as a functional group and the ketoses sugar possesses ketone as a functional group.

Monosaccharides are also classified on the basis of the number of carbon atoms present in it.  For example, the sugar that contains five carbon atoms is known as pentoses sugar and the sugar that contains six carbon atoms is known as hexoses sugar.

Answer to Problem 18.62EP

The monosaccharide, $\text{D}-\text{glucose}$ is an aldohexoses and the monosaccharide $\text{D}-\text{ribose}$ is an aldopentoses.

Explanation of Solution

The monosaccharide, $\text{D}-\text{glucose}$ is an aldohexose sugar because it contains six carbon atoms attached with an aldehydic functional group as shown below.

The second sugar, $\text{D}-\text{ribose}$ is also an aldopentoses sugar because it contains five carbon atoms with an aldehydic functional group as shown below.

(b)

Interpretation Introduction

Interpretation: Among the given terms aldoses, ketoses, hexoses and aldohexoses, the term that is applied to both $\text{D}-\text{frustose}$ and $\text{D}-\text{dihydroxyacetone}$ has to be predicted.

Concept introduction: The simplest hydrolyzed form that is obtained from the carbohydrates is known as monosaccharide.  Monosaccharide is categorized into two types.  The first type of monosaccharide is aldoses and the second type of monosaccharide is ketoses.  Aldoses sugar possesses aldehyde as a functional group and the ketoses sugar possesses ketone as a functional group.

Monosaccharides are also classified on the basis of the number of carbon atoms present in it.  For example, the sugar that contains five carbon atoms is known as pentoses sugar and the sugar that contains six carbon atoms is known as hexoses sugar.

Answer to Problem 18.62EP

The monosaccharide, $\text{D}-\text{frustose}$ is a ketohexoses and the monosaccharide $\text{D}-\text{dihydroxyacetone}$ is a ketotriose.

Explanation of Solution

The monosaccharide, $\text{D}-\text{frustose}$ is a ketohexose sugar because it contains six carbon atoms attached with a ketonic functional group as shown below.

The second sugar, $\text{D}-\text{dihydroxyacetone}$ is a ketotriose sugar because it contains three carbon atoms attached with a ketonic functional group as shown below.

(c)

Interpretation Introduction

Interpretation: Among the given terms aldoses, ketoses, hexoses and aldohexoses, the term that is applied to both $\text{D}-\text{glyceraldehyde}$ and $\text{D}-\text{dihydroxyacetone}$ has to be predicted.

Concept introduction: The simplest hydrolyzed form that is obtained from the carbohydrates is known as monosaccharide.  Monosaccharide is categorized into two types.  The first type of monosaccharide is aldoses and the second type of monosaccharide is ketoses.  Aldoses sugar possesses aldehyde as a functional group and the ketoses sugar possesses ketone as a functional group.

Monosaccharides are also classified on the basis of the number of carbon atoms present in it.  For example, the sugar that contains five carbon atoms is known as pentoses sugar and the sugar that contains six carbon atoms is known as hexoses sugar.

Answer to Problem 18.62EP

The monosaccharide, $\text{D}-\text{glyceraldehyde}$ is an aldotriose and the monosaccharide $\text{D}-\text{dihydroxyacetone}$ is a ketotriose.

Explanation of Solution

The monosaccharide, $\text{D}-\text{glyceraldehyde}$ is an aldotriose sugar because it contains three carbon atoms with an aldehydic functional group as shown below.

The second sugar, $\text{D}-\text{dihydroxyacetone}$ is a ketotriose sugar because it contains three carbon atoms attached with a ketonic functional group as shown below.

(d)

Interpretation Introduction

Interpretation: Among the given terms aldoses, ketoses, hexoses and aldohexoses, the term that is applied to both $\text{D}-\text{galactose}$ and $\text{D}-\text{ribose}$ has to be predicted.

Concept introduction: The simplest hydrolyzed form that is obtained from the carbohydrates is known as monosaccharide.  Monosaccharide is categorized into two types.  The first type of monosaccharide is aldoses and the second type of monosaccharide is ketoses.  Aldoses sugar possesses aldehyde as a functional group and the ketoses sugar possesses ketone as a functional group.

Monosaccharides are also classified on the basis of the number of carbon atoms present in it.  For example, the sugar that contains five carbon atoms is known as pentoses sugar and the sugar that contains six carbon atoms is known as hexoses sugar.

Answer to Problem 18.62EP

The monosaccharide, $\text{D}-\text{galactose}$ is an aldohexoses and the monosaccharide $\text{D}-\text{ribose}$ is an aldopentoses.

Explanation of Solution

The monosaccharide, $\text{D}-\text{galactose}$ is an aldohexose sugar because it contains six carbon atoms with an aldehydic functional group as shown below.

The second sugar, $\text{D}-\text{ribose}$ is also an aldopentoses sugar because it contains five carbon atoms with an aldehydic functional group as shown below.