Chapter 20, Problem 67A

(a)

Interpretation Introduction

Interpretation: The structure of 2-methylpentanal needs to be drawn.

Concept Introduction: Alkanes are the saturated hydrocarbons which are mainly composed of C and H atoms. The carbon atoms are bonded in straight chain or branched chain. Alkyl halides are the halogens derivatives of alkanes. They have certain heteroatoms as Cl, I, Br or F along with C and H atoms.

The IUPAC rules are purposed to names different alkanes and alkyl halides.

Answer to Problem 67A

  

Explanation of Solution

According to IUPAC rule:

• Root word will be determined on the basis of number of C atoms in the longest chain.
• The primary suffix must be determined on the basis of covalent bonds between carbon atoms of the parent chain. They can be −ane, -ene and −yne.
• The secondary suffix indicates the presence of functional group in the molecule.
• The prefix in the IUPAC name indicates the presence of side chain or certain groups like halogens.

In 2-methylpentanal, pent- is root word so there must be 5 C atoms in chain with one methyl group at C-2 and one −CHO group at C-1.

  

(b)

Interpretation Introduction

Interpretation: The structure of 3-hydroxybutanoic acid needs to be drawn.

Concept Introduction: Alkanes are the saturated hydrocarbons which are mainly composed of C and H atoms. The carbon atoms are bonded in straight chain or branched chain. Alkyl halides are the halogens derivatives of alkanes. They have certain heteroatoms as Cl, I, Br or F along with C and H atoms.

The IUPAC rules are purposed to names different alkanes and alkyl halides.

Answer to Problem 67A

  

Explanation of Solution

According to IUPAC rule:

• Root word will be determined on the basis of number of C atoms in the longest chain.
• The primary suffix must be determined on the basis of covalent bonds between carbon atoms of the parent chain. They can be −ane, -ene and −yne.
• The secondary suffix indicates the presence of functional group in the molecule.
• The prefix in the IUPAC name indicates the presence of side chain or certain groups like halogens.

In 3-hydroxybutanoic acid, but- is root word so there must be 4 C atoms in chain with one hydroxy group at C-3 and one −COOH group at C-1.

  

(c)

Interpretation Introduction

Interpretation: The structure of 2-aminopropanal needs to be drawn.

Concept Introduction: Alkanes are the saturated hydrocarbons which are mainly composed of C and H atoms. The carbon atoms are bonded in straight chain or branched chain. Alkyl halides are the halogens derivatives of alkanes. They have certain heteroatoms as Cl, I, Br or F along with C and H atoms.

The IUPAC rules are purposed to names different alkanes and alkyl halides.

Answer to Problem 67A

  

Explanation of Solution

According to IUPAC rule:

• Root word will be determined on the basis of number of C atoms in the longest chain.
• The primary suffix must be determined on the basis of covalent bonds between carbon atoms of the parent chain. They can be −ane, -ene and −yne.
• The secondary suffix indicates the presence of functional group in the molecule.
• The prefix in the IUPAC name indicates the presence of side chain or certain groups like halogens.

In 2-aminopropanal, prop- is root word so there must be 3 C atoms in chain with one amino group at C-2 and one −CHO group at C-1.

  

(d)

Interpretation Introduction

Interpretation: The structure of 2,4-hexanedione needs to be determined.

Concept Introduction: Alkanes are the saturated hydrocarbons which are mainly composed of C and H atoms. The carbon atoms are bonded in straight chain or branched chain. Alkyl halides are the halogens derivatives of alkanes. They have certain heteroatoms as Cl, I, Br or F along with C and H atoms.

The IUPAC rules are purposed to names different alkanes and alkyl halides.

Answer to Problem 67A

  

Explanation of Solution

According to IUPAC rule:

• Root word will be determined on the basis of number of C atoms in the longest chain.
• The primary suffix must be determined on the basis of covalent bonds between carbon atoms of the parent chain. They can be −ane, -ene and −yne.
• The secondary suffix indicates the presence of functional group in the molecule.
• The prefix in the IUPAC name indicates the presence of side chain or certain groups like halogens.

In 2,4-hexanedione, hex- is root word so there must be 6 C atoms in chain with two ketone groups at C-2 and C-4.

  

(e)

Interpretation Introduction

Interpretation: The structure of 3-methylbenzaldehyde needs to be determined.

Concept Introduction: Alkanes are the saturated hydrocarbons which are mainly composed of C and H atoms. The carbon atoms are bonded in straight chain or branched chain. Alkyl halides are the halogens derivatives of alkanes. They have certain heteroatoms as Cl, I, Br or F along with C and H atoms.

The IUPAC rules are purposed to names different alkanes and alkyl halides.

Answer to Problem 67A

  

Explanation of Solution

According to IUPAC rule:

• Root word will be determined on the basis of number of C atoms in the longest chain.
• The primary suffix must be determined on the basis of covalent bonds between carbon atoms of the parent chain. They can be −ane, -ene and −yne.
• The secondary suffix indicates the presence of functional group in the molecule.
• The prefix in the IUPAC name indicates the presence of side chain or certain groups like halogens.

In 3-methylbenzaldehyde, benzene ring should be root word with one aldehyde group and one methyl at C-3 position.