Chapter 3, Problem 31P

a. Identify the functional groups in the ball-and-stick model of elemicin, a compound partly responsible f or the flavor and fragrance of nutmeg.

b. Draw a skeletal structure of a constitutional isomer of elemicin that should have a higher boiling point and melting point.

c. Label all electrophilic carbon atoms.

Interpretation Introduction

(a)

Interpretation: The functional groups in the ball-and-stick model of elemicin are to be identified.

Concept introduction: An atom or a group of atoms which are responsible for characteristic physical and chemical properties of the compound are collectively known as functional groups. The functional groups are the most reactive part present in the molecule.

Answer to Problem 31P

The functional groups present in the ball-and-stick model of elemicin are ether and alkene group.

Explanation of Solution

The given molecule is,

Figure 1

The red coloured balls have two bonds. So, these are the oxygen atoms. Black coloured atoms have four bonds. So, these are the carbon atoms. The grey coloured balls have one bond. So, these are the hydrogen atoms. The molecular structure of elemicin is,

Figure 2

The functional groups present in the ball-and-stick model of elemicin are ether and alkene group.

Conclusion

The functional groups present in the ball-and-stick model of elemicin are ether and alkene group.

Interpretation Introduction

(b)

Interpretation: The skeletal structure of a constitutional isomer of elemicin that should have a higher boiling point and melting point is to be drawn.

Concept introduction: The isomers which have same molecular formula but different connectivity of atoms are constitutional isomers.

The temperature at which the vapour pressure of a substance becomes equal to the pressure surrounding the liquid is boiling point. The boiling point depends on the intermolecular forces. Stronger the intermolecular force, higher is the boiling point.

The temperature at which the solid converts to its liquid phase is melting point. Stronger the intermolecular force, higher is the boiling point.

Answer to Problem 31P

The skeletal structure of a constitutional isomer of elemicin that should have a higher boiling point and melting point is shown below.

Explanation of Solution

The skeletal structure of a constitutional isomer of elemicin that should have a higher boiling point and melting point is,

Figure 3

This structure contains alcohol groups. This structure exhibits intermolecular hydrogen bonding due to the presence of hydrogen atoms bonded to oxygen atom. Hydrogen bonding is strongest intermolecular forces.

Conclusion

The skeletal structure of a constitutional isomer of elemicin that should have a higher boiling point and melting point is shown in Figure 3.

Interpretation Introduction

(c)

Interpretation: All electrophilic carbon atoms are to be labeled.

Concept introduction: An electron deficient due to hetero atoms or pi bonds or both is electrophilic site and an electron rich site due to hetero atoms or pi bonds or both is nucleophilic site.

Answer to Problem 31P

The carbon atoms attached to the oxygen atom in ether group are electrophilic in nature.

Explanation of Solution

An oxygen atom is more electronegative than carbon atom which makes the carbon atom attached to oxygen atom electron deficient and electrophilic site as shown below.

Figure 4

Conclusion

The carbon atoms attached to the oxygen atom in ether group are electrophilic in nature.