Chapter 20, Problem 54A

(a)

Interpretation Introduction

Interpretation:

The systematic name of given compound is to be written.

Concept introduction:

The compounds are named as per IUPAC rules.

To name a compound, general pattern which is used is:

Prefix + word-root + suffix

Answer to Problem 54A

3-Methylbutanoic acid

Explanation of Solution

  $-COOH$ in the structure shows that the compound is carboxylic acid.

The numbering is done from right side to give carboxylic group number 1. ‘oic acid’ suffix is used to indicate carboxylic group.

The chain contains four carbon atoms which are single bonded. So word-root ‘butan’ is used. ‘e’ is removed as per the rules.

The skeleton shows one methyl is attached at C-3. Therefore, name of compound is 3-Methylbutanoic acid

(b)

Interpretation Introduction

Interpretation:

The systematic name of given compound is to be written.

Concept introduction:

The compounds are named as per IUPAC rules.

To name a compound, general pattern which is used is:

Prefix + word-root + suffix

Answer to Problem 54A

Benzenecarboxylic acid

Explanation of Solution

  $-COOH$ in the structure shows that the compound is carboxylic acid. Benzene ring shows it is aromatic acid.

  $-COOH$ is directly attached to benzene ring. So its name is Benzenecarboxylic acid. Its other name is benzoic acid.

(c)

Interpretation Introduction

Interpretation:

The systematic name of given compound is to be written.

Concept introduction:

The compounds are named as per IUPAC rules.

To name a compound, general pattern which is used is:

Prefix + word-root + suffix

Answer to Problem 54A

2-Hydroxypropanoic acid

Explanation of Solution

  $-COOH$ in the structure shows that the compound is carboxylic acid and $-OH$ shows it is alcohol. But carboxylic acid is primary functional group and alcohol is secondary functional group. So it is treated as substituent.

The numbering is done from right side to give carboxylic group number 1. ‘oic acid’ suffix is used to indicate carboxylic group.

The chain contains three carbon atoms which are single bonded. So word-root ‘propan’ is used. ‘e’ is removed as per the rules.

The skeleton shows one hydroxyl is attached at C-2. Therefore, name of compound is2-Hydroxypropanoic acid

(d)

Interpretation Introduction

Interpretation:

The systematic name of given compound is to be written.

Concept introduction:

The compounds are named as per IUPAC rules.

To name a compound, general pattern which is used is:

Prefix + word-root + suffix

Answer to Problem 54A

3,4-Dimethylhexanoic acid

Explanation of Solution

  $-COOH$ in the structure shows that the compound is carboxylic acid.

The numbering is done from right side to give carboxylic group number 1. ‘oic acid’ suffix is used to indicate carboxylic group.

The chain contains six carbon atoms which are single bonded. So word-root ‘hexan’ is used. ‘e’ is removed as per the rules.

The skeleton shows two methyl groups are attached one at C-3 and other at C-4. Therefore, name of compound is 3,4-Dimethylhexanoic acid