Chapter 18, Problem 18.50EP

(a)

Interpretation Introduction

Interpretation: Whether the solubility in water will be the same or different for the compounds $\left(\text{+}\right)-\text{glyceraldehyde}$ and $(-)-\text{glyceraldehyde}$ has to be predicted.

Concept introduction: Glyceraldehyde is an aldose which is the simplest monosaccharide that exists with three carbon atoms.  Glyceraldehyde exists in two different forms, $\left(\text{+}\right)-\text{glyceraldehyde}$ and $(-)-\text{glyceraldehyde}$.  These two forms of glyceraldehyde are enantiomers.

Answer to Problem 18.50EP

The solubility in water for $\left(\text{+}\right)-\text{glyceraldehyde}$ and $(-)-\text{glyceraldehyde}$ is same.

Explanation of Solution

The most of the properties of $\left(\text{+}\right)-\text{glyceraldehyde}$ and $(-)-\text{glyceraldehyde}$ are same.  But the properties involving the interaction with the plane polarised light and other chiral molecules, like solubility in a chiral solvent will be different.  The solubility in water of $\left(\text{+}\right)-\text{glyceraldehyde}$ and $(-)-\text{glyceraldehyde}$ will be similar.

Hence, the solubility in water for $\left(\text{+}\right)-\text{glyceraldehyde}$ and $(-)-\text{glyceraldehyde}$ is same.

(b)

Interpretation Introduction

Interpretation: Whether the reaction with $\left(\text{+}\right)-\text{2,3}-\text{butanediol}$ will be the same or different for the compounds $\left(\text{+}\right)-\text{glyceraldehyde}$ and $(-)-\text{glyceraldehyde}$ has to be predicted.

Concept introduction: Glyceraldehyde is an aldose which is the simplest monosaccharide that exists with three carbon atoms.  Glyceraldehyde exists in two different forms, $\left(\text{+}\right)-\text{glyceraldehyde}$ and $(-)-\text{glyceraldehyde}$.  These two forms of glyceraldehyde are enantiomers.

Answer to Problem 18.50EP

The given property for $\left(\text{+}\right)-\text{glyceraldehyde}$ and $(-)-\text{glyceraldehyde}$ is different.

Explanation of Solution

The most of the properties of $\left(\text{+}\right)-\text{glyceraldehyde}$ and $(-)-\text{glyceraldehyde}$ are same.  But the properties involving the interaction with the plane polarised light and other chiral molecules, like solubility in a chiral solvent will be different.  Reaction of $\left(\text{+}\right)-\text{glyceraldehyde}$ and $(-)-\text{glyceraldehyde}$ with $\left(\text{+}\right)-\text{2,3}-\text{butanediol}$ will be different.

Hence, the reaction with $\left(\text{+}\right)-\text{2,3}-\text{butanediol}$ for $\left(\text{+}\right)-\text{glyceraldehyde}$ and $(-)-\text{glyceraldehyde}$ is different.

(c)

Interpretation Introduction

Interpretation: Whether the rotation of plane polarised light will be the same or different for the compounds $\left(\text{+}\right)-\text{glyceraldehyde}$ and $(-)-\text{glyceraldehyde}$ has to be predicted.

Concept introduction: Glyceraldehyde is an aldose which is the simplest monosaccharide that exists with three carbon atoms.  Glyceraldehyde exists in two different forms, $\left(\text{+}\right)-\text{glyceraldehyde}$ and $(-)-\text{glyceraldehyde}$.  These two forms of glyceraldehyde are enantiomers.

Answer to Problem 18.50EP

The rotation of plane polarised light for $\left(\text{+}\right)-\text{glyceraldehyde}$ and $(-)-\text{glyceraldehyde}$ is different.

Explanation of Solution

The most of the properties of $\left(\text{+}\right)-\text{glyceraldehyde}$ and $(-)-\text{glyceraldehyde}$ are same. But the properties involving the interaction with the plane polarised light and other chiral molecules, like solubility in a chiral solvent will be different.

Hence, the rotation of plane polarised light for $\left(\text{+}\right)-\text{glyceraldehyde}$ and $(-)-\text{glyceraldehyde}$ is different.

(d)

Interpretation Introduction

Interpretation: Whether the reaction with methanol will be the same or different for the compounds $\left(\text{+}\right)-\text{glyceraldehyde}$ and $(-)-\text{glyceraldehyde}$ has to be predicted.

Concept introduction: Glyceraldehyde is an aldose which is the simplest monosaccharide that exists with three carbon atoms.  Glyceraldehyde exists in two different forms, $\left(\text{+}\right)-\text{glyceraldehyde}$ and $(-)-\text{glyceraldehyde}$.  These two forms of glyceraldehyde are enantiomers.

Answer to Problem 18.50EP

The reaction with methanol for $\left(\text{+}\right)-\text{glyceraldehyde}$ and $(-)-\text{glyceraldehyde}$ is same.

Explanation of Solution

The two forms of glyceraldehyde, $\left(\text{+}\right)-\text{glyceraldehyde}$ and $(-)-\text{glyceraldehyde}$ are enantiomers.  Therefore, most of the properties of $\left(\text{+}\right)-\text{glyceraldehyde}$ and $(-)-\text{glyceraldehyde}$ are same.  But the properties involving the interaction with the plane polarised light and other chiral molecules, like solubility in a chiral solvent will be different.  The reaction of $\left(\text{+}\right)-\text{glyceraldehyde}$ and $(-)-\text{glyceraldehyde}$ with methanol will be similar.