Chapter 4, Problem 4.21EP

(a)

Interpretation Introduction

Interpretation:

Structural formula for the given aldehyde has to be drawn.

Concept Introduction:

Structure of the aldehyde can be drawn from the IUPAC name.  In the IUPAC name, the parent chain of carbon atom can be identified and then the substituents present in it can also be identified.  With these information, the structure for the given compound can be drawn.  In an aldehyde the counting has to be always from the carbonyl carbon that is given the number 1.

The structural representation of organic compound can be done in 2D and 3D.  In two-dimensional representation, there are four types of representation in which an organic compound can be drawn.  They are,

• • Expanded structural formula
• • Condensed structural formula
• • Skeletal structural formula
• • Line-angle structural formula

Structural formula which shows all the atoms in a molecule along with all the bonds that is connecting the atoms present in the molecule is known as Expanded structural formula.

Structural formula in which grouping of atoms are done and in which the central atoms along with the other atoms are connected to them are treated as group is known as Condensed structural formula.

Structural formula that shows the bonding between carbon atoms alone in the molecule ignoring the hydrogen atoms being shown explicitly is known as Skeletal structural formula.

Structural formula where a line represent carbon‑carbon bond and the carbon atom is considered to be present in each point and the end of lines is known as Line-angle structural formula.

Answer to Problem 4.21EP

The structural formula for 3-methylpentanal is,

Explanation of Solution

The given name of the compound is 3-methylpentanal.  From the name it is understood that the parent carbon chain is pentane and it contains five carbon atoms.  The parent chain can be drawn as shown below,

From the name of the given aldehyde, the substituents that are present can be identified.  In this case, the substituent is a methyl group on third carbon atom.  The first carbon atom has to be the carbonyl carbon atom as the given compound is an aldehyde.

Carbon atom has a valence of four.  Hence, carbon atom can form four covalent bonds.  The remaining bonds are satisfied by hydrogen atom.  The structure is obtained as shown below,

Conclusion

Structural formula for the given aldehyde is drawn.

(b)

Interpretation Introduction

Interpretation:

Structural formula for the given aldehyde has to be drawn.

Concept Introduction:

Structure of the aldehyde can be drawn from the IUPAC name.  In the IUPAC name, the parent chain of carbon atom can be identified and then the substituents present in it can also be identified.  With these information, the structure for the given compound can be drawn.  In an aldehyde the counting has to be always from the carbonyl carbon that is given the number 1.

The structural representation of organic compound can be done in 2D and 3D.  In two-dimensional representation, there are four types of representation in which an organic compound can be drawn.  They are,

• • Expanded structural formula
• • Condensed structural formula
• • Skeletal structural formula
• • Line-angle structural formula

Structural formula which shows all the atoms in a molecule along with all the bonds that is connecting the atoms present in the molecule is known as Expanded structural formula.

Structural formula in which grouping of atoms are done and in which the central atoms along with the other atoms are connected to them are treated as group is known as Condensed structural formula.

Structural formula that shows the bonding between carbon atoms alone in the molecule ignoring the hydrogen atoms being shown explicitly is known as Skeletal structural formula.

Structural formula where a line represent carbon‑carbon bond and the carbon atom is considered to be present in each point and the end of lines is known as Line-angle structural formula.

Answer to Problem 4.21EP

The structural formula for 2-ethylhexanal is,

Explanation of Solution

The given name of the compound is 2-ethylhexanal.  From the name it is understood that the parent carbon chain is hexane and it contains six carbon atoms.  The parent chain can be drawn as shown below,

From the name of the given aldehyde, the substituents that are present can be identified.  In this case, the substituent is an ethyl group on second carbon atom.  The first carbon atom has to be the carbonyl carbon atom as the given compound is an aldehyde.

Carbon atom has a valence of four.  Hence, carbon atom can form four covalent bonds.  The remaining bonds are satisfied by hydrogen atom.  The structure is obtained as shown below,

Conclusion

Structural formula for the given aldehyde is drawn.

(c)

Interpretation Introduction

Interpretation:

Structural formula for the given aldehyde has to be drawn.

Concept Introduction:

Structure of the aldehyde can be drawn from the IUPAC name.  In the IUPAC name, the parent chain of carbon atom can be identified and then the substituents present in it can also be identified.  With these information, the structure for the given compound can be drawn.  In an aldehyde the counting has to be always from the carbonyl carbon that is given the number 1.

The structural representation of organic compound can be done in 2D and 3D.  In two-dimensional representation, there are four types of representation in which an organic compound can be drawn.  They are,

• • Expanded structural formula
• • Condensed structural formula
• • Skeletal structural formula
• • Line-angle structural formula

Structural formula which shows all the atoms in a molecule along with all the bonds that is connecting the atoms present in the molecule is known as Expanded structural formula.

Structural formula in which grouping of atoms are done and in which the central atoms along with the other atoms are connected to them are treated as group is known as Condensed structural formula.

Structural formula that shows the bonding between carbon atoms alone in the molecule ignoring the hydrogen atoms being shown explicitly is known as Skeletal structural formula.

Structural formula where a line represent carbon‑carbon bond and the carbon atom is considered to be present in each point and the end of lines is known as Line-angle structural formula.

Answer to Problem 4.21EP

The structural formula for 2,2-dichloropropanal is,

Explanation of Solution

The given name of the compound is 2,2-dichloropropanal.  From the name it is understood that the parent carbon chain is propane and it contains three carbon atoms.  The parent chain can be drawn as shown below,

From the name of the given aldehyde, the substituents that are present can be identified.  In this case, the substituents are two chlorine atoms on second carbon atom.  The first carbon atom has to be the carbonyl carbon atom as the given compound is an aldehyde.

Carbon atom has a valence of four.  Hence, carbon atom can form four covalent bonds.  The remaining bonds are satisfied by hydrogen atom.  The structure is obtained as shown below,

Conclusion

Structural formula for the given aldehyde is drawn.

(d)

Interpretation Introduction

Interpretation:

Structural formula for the given aldehyde has to be drawn.

Concept Introduction:

Structure of the aldehyde can be drawn from the IUPAC name.  In the IUPAC name, the parent chain of carbon atom can be identified and then the substituents present in it can also be identified.  With these information, the structure for the given compound can be drawn.  In an aldehyde the counting has to be always from the carbonyl carbon that is given the number 1.

The structural representation of organic compound can be done in 2D and 3D.  In two-dimensional representation, there are four types of representation in which an organic compound can be drawn.  They are,

• • Expanded structural formula
• • Condensed structural formula
• • Skeletal structural formula
• • Line-angle structural formula

Structural formula which shows all the atoms in a molecule along with all the bonds that is connecting the atoms present in the molecule is known as Expanded structural formula.

Structural formula in which grouping of atoms are done and in which the central atoms along with the other atoms are connected to them are treated as group is known as Condensed structural formula.

Structural formula that shows the bonding between carbon atoms alone in the molecule ignoring the hydrogen atoms being shown explicitly is known as Skeletal structural formula.

Structural formula where a line represent carbon‑carbon bond and the carbon atom is considered to be present in each point and the end of lines is known as Line-angle structural formula.

Answer to Problem 4.21EP

The structural formula for 4-hydroxy-2-methyloctanal is,

Explanation of Solution

The given name of the compound is 4-hydroxy-2-methyloctanal.  From the name it is understood that the parent carbon chain is octane and it contains eight carbon atoms.  The parent chain can be drawn as shown below,

From the name of the given aldehyde, the substituents that are present can be identified.  In this case, the substituents are a methyl group on second carbon atom and a hydroxyl group on fourth carbon atom.  The first carbon atom has to be the carbonyl carbon atom as the given compound is an aldehyde.

Carbon atom has a valence of four.  Hence, carbon atom can form four covalent bonds.  The remaining bonds are satisfied by hydrogen atom.  The structure is obtained as shown below,

Conclusion

Structural formula for the given aldehyde is drawn.