Chapter 23, Problem 70PS

(a)

Interpretation Introduction

Interpretation: The result of treating compound 1 with ${\text{NaBH}}_{\text{4}}$ has to be given. The functional group and the name of the product has to be identified

Concept introduction:

Reduction reaction: The reaction in which addition of hydrogen takes place is known as reduction reaction.

The reduction of a ketone gives a secondary alcohol. The reduction can be carried out by using hydride reagents such as ${\text{NaBH}}_{\text{4}}{\text{ and LiAlH}}_{\text{4}}$.

Alcohols are the hydrocarbons which have $\text{OH}$ group attached to one of the carbon atom of the linear chain. The suffix name for $\text{OH}$ group is “-ol” written in the end of parent name with its position.

Alcohols can be of three types on the basis of degree of carbon atom to which the $\text{OH}$ group is attached.

Primary alcohol: The $\text{OH}$ group is attached to primary carbon atom.

Secondary alcohol: The $\text{OH}$ group is attached to secondary carbon atom

Tertiary alcohol: The $\text{OH}$ group is attached to tertiary carbon atom

Answer to Problem 70PS

The product obtained from the reaction of given compound $1$ and ${\text{NaBH}}_{\text{4}}$ is a secondary alcohol. The structure of the product is drawn below.

  

The systematic name of the product is 2-butanol and functional group is alcohol.

Explanation of Solution

Compound 1 s,

It is a ketone

The reaction between compound $1$ and ${\text{NaBH}}_{\text{4}}$ is the reduction reaction of a ketone.

The reduction of a ketone gives a secondary alcohol in presence of ${\text{NaBH}}_{\text{4}}$

The reaction is in which the compound $1$ is undergoing reduction gives a secondary alcohol.

The product has same number of carbon atoms as in compound $1$ that is four carbon atoms.

The parent chain name will be butane and suffix will be “-ol” as there is one $\text{OH}$ group at $\text{C-2}$ position.

Therefore, name of the product is 2-butanol and functional group is alcohol.

(b)

Interpretation Introduction

Interpretation: The structure of the reaction product from comounds 2 and 4 has to be drawn. The functional group of the product has to be identified

Concept introduction:

Ester: One $-OR\text{'}$ group is attached to the carbonyl carbon atom of the compound. It is represented as $RCOOR\text{'}$. The hydrogen atom of $-COOH$ is replaced by an alkyl group.

The name for an ester molecule can be written by using alkyl chain $\text{R'}$ for prefix of the parent name. The IUPAC name for the esters is written by replacing the ‘e’ of alkane R to ‘oate’

Esterification reaction: Esters are prepared by the reaction of a carboxylic acid and an alcohol molecule with the elimination of water molecule. The addition of a strong acid such as ${\text{H}}_{\text{2}}{\text{SO}}_{\text{4}}$ is used to increase the rate of reaction.

Here, the $-OH$ group is attached to the carbonyl carbon atom of the carboxylic acid is being replaced by $-OR\text{'}$ the in the alcohol forming ester and water.

Answer to Problem 70PS

The structure of the product is,

  

The functional group is an ester

Explanation of Solution

Compound 2 is,

  

It is a carboxylic acid

Compound 4 is,

  

It is a secondary alcohol

Esters are prepared by the reaction of a carboxylic acid and an alcohol molecule with the elimination of water molecule

The reaction is written below in which the compound $2$ is undergoing condensation with compound $4$, i.e., secondary alcohol. The functional group of the product is ester.

Here, the $-OH$ group is attached to the carbonyl carbon atom of the carboxylic acid (compound 2) is being replaced by $-OR\text{'}$ the in the alcohol (compound 4) forming ester and water.

The product has $-COO-$ group and hence is an ester.

(c)

Interpretation Introduction

Interpretation: The compound that results from the addition of $H_2$ to compound 3 has to be given. The name of the product has to be identified

Concept introduction:

Hydrogenation: The addition of hydrogen to unsaturated compounds to convert into saturated compounds in the presence of catalyst.

An alkene undergo hydrogentaion reaction when it is treated with hydrogen gas. The addition of two hydrogen atoms takes place on the carbon-carbon double bond. The product formed is called as alkane as there will be only carbon-carbon single bonds in the molecule.

Alcohols are the hydrocarbons which have $\text{OH}$ group attached to one of the carbon atom of the linear chain. The suffix name for $\text{OH}$ group is “-ol” written in the end of parent name with its position.

Alcohols can be of three types on the basis of degree of carbon atom to which the $\text{OH}$ group is attached.

Answer to Problem 70PS

The product obtained from the reaction of given compound $3$ and ${\text{H}}_2$ is,

  

Explanation of Solution

Compound 3 is,

It is an alkene

The reaction between compound $3$ and ${\text{H}}_{\text{2}}$ is the reduction reaction of an alkene.

In this reaction, the compound $3$ undergoes reduction and gives a primary alcohol.

The product has same number of carbon atoms as in compound $3$ that is four carbon atoms.

The parent chain name will be butane

The suffix will be “-ol” as there is one $\text{OH}$ group at $\text{C-1}$ position.

Therefore, name of the product is 1-butanol and functional group is alcohol.

(d)

Interpretation Introduction

Interpretation: The compound that results from the addition of $NaOH$ to compound 2 has to be given.

Concept introduction:

The reaction of carboxylic acid with $\text{NaOH}$ is the neutralization reaction of an acid with base. The product obtained is the sodium salt of the acid and water.

Answer to Problem 70PS

The product obtained from the reaction of given compound $2$ and $\text{NaOH}$ is,

  

Explanation of Solution

The reaction of carboxylic acid with $\text{NaOH}$ is the neutralization reaction of an acid with base.

The product obtained is the sodium salt of the acid and water.

The reaction of compound $2$ and $\text{NaOH}$ is written below.