Chapter 9, Problem 20Q

(a)

Interpretation Introduction

Interpretation:

The name for carboxylic acid that contains five carbons with it has to be given.

Concept Introduction:

Functional group: They are certain substitutes in the organic molecules which determine the characteristic reactions taking place in it.

Any organic molecule can be named by using certain rules given by IUPAC (International Union for Pure and applied chemistry). IUPAC name consists of three parts, namely Prefix, suffix and root word.

Prefix- Represents the substituent present in the molecule and its position in the root name.

Suffix denotes the presence of functional group if any in the molecule. It can be an alkene, alkyne, alcohol, carboxylic acid, alcohol etc...

Root word - Represents the longest continuous carbon skeleton of the organic molecule.

When a molecule consists of cyclic structure, the root word of the molecule is prefixed with cyclo, if it is two cyclic structure combined then prefixed with bicyclo.

$\begin{array}{ccc}\text{Functional group}& \text{Suffix name}& \text{Prefix name}\\ \text{Carboxylic acid}& \text{-oic acid}& \text{Carboxy}\\ \text{Ester}& \text{-oate}& \text{Alkoxy carbonyl}\\ \text{Amide}& \text{-amide}& \text{Amido}\\ \text{Nitrile}& \text{-ntrile}& \text{Cyano}\\ \text{Aldehyde}& \text{-al}& \text{Oxo(=O)}\\ \text{Aldehyde}& \text{-al}& \text{Formyl(-CH=O)}\\ \text{Ketone}& \text{-one}& \text{Oxo(=O)}\\ \text{Alcohol}& \text{-ol}& \text{Hydroxy}\\ \text{Amine}& \text{-amine}& \text{Amino}\\ \text{Alkene}& \text{-ene}& \text{Alkenyl}\\ \text{Alkyne}& \text{-yne}& \text{Alkynyl}\\ \text{Alkane}& \text{-ane}& \text{Alkyl}\\ \text{Ether}& \text{---}& \text{Alkoxy}\\ \text{Alkylhalide}& \text{---}& \text{Halo}\end{array}$

Explanation of Solution

The given condition says that carboxylic acid contains $5$ carbons with it. Hence, the longest carbon chain is pentane and the function group present in the compound is carboxylic acid.

Therefore, as per IUPAC rules the root word has to be suffixed with ‘oic acid’.

The name for given carboxylic acid is pentanoic acid.

(b)

Interpretation Introduction

Interpretation:

The structural formula of methanoic acid has to be drawn.

Concept Introduction:

The Structural formula of a compound shows how the atoms are arranged in a molecule and, in particular, shows which functional groups are present.

Functional group: They are certain substitutes in the organic molecules which determine the characteristic reactions taking place in it.

Any organic molecule can be named by using certain rules given by IUPAC (International Union for Pure and applied chemistry). IUPAC name consists of three parts, namely Prefix, suffix and root word.

Prefix- Represents the substituent present in the molecule and its position in the root name.

Suffix denotes the presence of functional group if any in the molecule. It can be an alkene, alkyne, alcohol, carboxylic acid, alcohol etc...

Root word - Represents the longest continuous carbon skeleton of the organic molecule.

When a molecule consists of cyclic structure, the root word of the molecule is prefixed with cyclo, if it is two cyclic structure combined then prefixed with bicyclo.

$\begin{array}{ccc}\text{Functional group}& \text{Suffix name}& \text{Prefix name}\\ \text{Carboxylic acid}& \text{-oic acid}& \text{Carboxy}\\ \text{Ester}& \text{-oate}& \text{Alkoxy carbonyl}\\ \text{Amide}& \text{-amide}& \text{Amido}\\ \text{Nitrile}& \text{-ntrile}& \text{Cyano}\\ \text{Aldehyde}& \text{-al}& \text{Oxo(=O)}\\ \text{Aldehyde}& \text{-al}& \text{Formyl(-CH=O)}\\ \text{Ketone}& \text{-one}& \text{Oxo(=O)}\\ \text{Alcohol}& \text{-ol}& \text{Hydroxy}\\ \text{Amine}& \text{-amine}& \text{Amino}\\ \text{Alkene}& \text{-ene}& \text{Alkenyl}\\ \text{Alkyne}& \text{-yne}& \text{Alkynyl}\\ \text{Alkane}& \text{-ane}& \text{Alkyl}\\ \text{Ether}& \text{---}& \text{Alkoxy}\\ \text{Alkylhalide}& \text{---}& \text{Halo}\end{array}$

Explanation of Solution

The given name methanoic acid clearly shows that the compound contains one carbon in which the functional group carboxylic acid present.

Therefore, the structural formula is as follows,

(c)

Interpretation Introduction

Interpretation:

The structural formula of butanoic acid has to be drawn.

Concept Introduction:

The Structural formula of a compound shows how the atoms are arranged in a molecule and, in particular, shows which functional groups are present.

Functional group: They are certain substitutes in the organic molecules which determine the characteristic reactions taking place in it.

Any organic molecule can be named by using certain rules given by IUPAC (International Union for Pure and applied chemistry). IUPAC name consists of three parts, namely Prefix, suffix and root word.

Prefix- Represents the substituent present in the molecule and its position in the root name.

Suffix denotes the presence of functional group if any in the molecule. It can be an alkene, alkyne, alcohol, carboxylic acid, alcohol etc...

Root word - Represents the longest continuous carbon skeleton of the organic molecule.

When a molecule consists of cyclic structure, the root word of the molecule is prefixed with cyclo, if it is two cyclic structure combined then prefixed with bicyclo.

$\begin{array}{ccc}\text{Functional group}& \text{Suffix name}& \text{Prefix name}\\ \text{Carboxylic acid}& \text{-oic acid}& \text{Carboxy}\\ \text{Ester}& \text{-oate}& \text{Alkoxy carbonyl}\\ \text{Amide}& \text{-amide}& \text{Amido}\\ \text{Nitrile}& \text{-ntrile}& \text{Cyano}\\ \text{Aldehyde}& \text{-al}& \text{Oxo(=O)}\\ \text{Aldehyde}& \text{-al}& \text{Formyl(-CH=O)}\\ \text{Ketone}& \text{-one}& \text{Oxo(=O)}\\ \text{Alcohol}& \text{-ol}& \text{Hydroxy}\\ \text{Amine}& \text{-amine}& \text{Amino}\\ \text{Alkene}& \text{-ene}& \text{Alkenyl}\\ \text{Alkyne}& \text{-yne}& \text{Alkynyl}\\ \text{Alkane}& \text{-ane}& \text{Alkyl}\\ \text{Ether}& \text{---}& \text{Alkoxy}\\ \text{Alkylhalide}& \text{---}& \text{Halo}\end{array}$

Explanation of Solution

The given name butanoic acid clearly shows that the compound contains four carbons in which the functional group carboxylic acid present at first carbon position.

Therefore, the structural formula is as follows,