Chapter 20, Problem 51A

(a)

Interpretation Introduction

Interpretation:

The systematic name for given compound is to be written.

Concept introduction:

To name a ketonic compound, following rules are applied.

• Firstly longest chain containing keto group is to be chosen.
• Then numbering is done giving keto group the smallest number.
• Suffix ‘one’ is used for ketonic group.
• The name is written in the order- prefix+wordroot+an+one.
• Position of ketonic group is to be mentioned using numbers.
• Each alphabet and numeric number is joined by ‘-‘

Answer to Problem 51A

3-Hexanone

Explanation of Solution

The longest chain is containing six carbon atoms. So ‘hex’ is used as word.

The chain contains single bonded carbon atoms so ‘ane’ is used.

The numbering is done form right side so that keto group gets smallest numbering. So name of compound is

3-Hexanone

(b)

Interpretation Introduction

Interpretation:

The systematic name for given compound is to be written.

Concept introduction:

To name aldehyde compounds, following rules are applied.

• Firstly longest chain containing aldehydic group is to be chosen.
• Then numbering is done giving aldehyde carbon number 1.
• Suffix ‘al’ is used for aldehydic group.
• The name is written in the order- prefix+wordroot+an+one.
• Position of aldehydic group need not to be mentioned using numbers.
• Each alphabet and numeric number is joined by ‘-‘
• Two numeric numbers are separated by commas.

Answer to Problem 51A

2,3-Dichlorobutanal

Explanation of Solution

The longest chain is containing four carbon atoms. So ‘but’ is used as wordroot.

The chain contains single bonded carbon atoms so ‘ane’ is used.

The numbering is done form right side so that aldehyde group gets number 1.

Chlorine atoms are present at C-2 and 3.They are written as prefixes.

So name of compound is

2,3-Dichlorobutanal

(c)

Interpretation Introduction

Interpretation:

The systematic name for given compound is to be written.

Concept introduction:

To name aldehydic compounds, following rules are applied.

• Firstly longest chain containing aldehydic group is to be chosen.
• Then numbering is done giving aldehyde carbon number 1.
• Suffix ‘al’ is used for aldehydic group.
• The name is written in the order- prefix+wordroot+an+one.
• Position of aldehydic group need not to be mentioned using numbers.
• Each alphabet and numeric number is joined by ‘-‘
• Two numeric numbers are separated by commas.

Answer to Problem 51A

3,4-Dimethylpentanal

Explanation of Solution

The longest chain is containing five carbon atoms. So ‘pent’ is used as wordroot.

The chain contains single bonded carbon atoms so ‘ane’ is used.

The numbering is done form right side so that aldehyde group gets number 1.

Methyl groups are present at C-3 and 4 as substituents.They are written as prefixes.

So name of compound is

3,4-Dimethylpentanal

(d)

Interpretation Introduction

Interpretation:

The systematic name for given compound is to be written.

Concept introduction:

To name aldehyde compounds, following rules are applied.

• Firstly longest chain containing aldehydic group is to be chosen.
• Then numbering is done giving aldehyde carbon number 1.
• Suffix ‘al’ is used for aldehydic group.
• The name is written in the order- prefix+wordroot+an+one.
• Position of aldehydic group need not to be mentioned using numbers.
• Each alphabet and numeric number is joined by ‘-‘
• Two numeric numbers are separated by commas.

Answer to Problem 51A

2-Methylpropanal

Explanation of Solution

The longest chain is containing three carbon atoms. So ‘prop’ is used as wordroot.

The chain contains single bonded carbon atoms so ‘ane’ is used.

The numbering is done form right side so that aldehyde group gets number 1.

Methyl group is present at C-2. It is written as prefix.

So name of compound is

2-Methylpropanal

(e)

Interpretation Introduction

Interpretation:

The systematic name for given compound is to be written.

Concept introduction:

To name a ketonic compound, following rules are applied.

• Firstly longest chain containing keto group is to be chosen.
• Then numbering is done giving keto group the smallest number.
• Suffix ‘one’ is used for ketonic group.
• The name is written in the order- prefix+wordroot+an+one.
• Position of ketonic group is to be mentioned using numbers.
• Each alphabet and numeric number is joined by ‘-‘

Answer to Problem 51A

1-Phenylpropanone

Explanation of Solution

The longest chain is containing three carbon atoms. So ‘prop’ is used as wordroot.

The chain contains single bonded carbon atoms so ‘ane’ is used.

The numbering is done form right side so that keto group gets number 1.

Phenyl group is present at C-1. It is written as prefix.

So name of compound is

1-Phenylpropanone