Chapter 10, Problem 63P

(a)

Interpretation Introduction

Interpretation:

The major product of given reaction should be given.

Concept introduction:

${\text{S}}_{\text{N}}\text{1}$reaction:

In the nucleophilic substitution reaction, the rate of reaction depends only on one reactant, which is involved in reaction is called unimolecular nucleophilic substitution reaction.

In ${\text{S}}_{\text{N}}\text{1}$ reaction, formation of carbocation by reliving of leaving group from reactant is the first step and second step is addition nucleophile to carbocation.

The rate determination step is formation of carbocation.

The stability order of carbocation is,

Tertiary > Secondary > Primary

Therefore, tertiary alcohols undergo substitution very fast than the secondary alcohols because tertiary carbocation is more stable than the secondary carbocation than the primary carbocation. Primary alcohol is less stable therefore it won’t undergoes ${\text{S}}_{\text{N}}\text{1}$ substitution reaction.

(b)

Interpretation Introduction

Interpretation:

The major product of given reaction should be given.

Concept introduction:

${\text{S}}_{\text{N}}2$reaction:

In the nucleophilic substitution reaction, the rate of reaction depends on reactant as well as nucleophile, which are involved in reaction is called bimolecular nucleophilic substitution reaction.

In ${\text{S}}_{\text{N}}2$ reaction, the reliving of leaving group from reactant and nucleophilic of attack takes place simultaneously.

Reactant and nucleophile are present at the rate determination step.

The order of species involving in ${\text{S}}_{\text{N}}2$ reaction is,

Tertiary < Secondary < Primary

(c)

Interpretation Introduction

Interpretation:

The major product of given reaction should be given.

Concept introduction:

Chromic Acid:

Chromic Acid (${\text{H}}_{\text{2}}{\text{CrO}}_{\text{4}}$) is used as an oxidising agent, primary alcohol oxidised in to acid, secondary alcohol oxidised in to ketone.

(d)

Interpretation Introduction

Interpretation:

The major product of given reaction should be given.

Concept introduction:

Dehydration reaction:

Removal of water molecule from the reaction when the alcohol is treated with strong acid like sulfuric acid.

The stability of carbocation is given below,

Tertiary carbocation is more stable than the secondary and primary.

(e)

Interpretation Introduction

Interpretation:

The major product of given reaction should be given.

Concept introduction:

In the presence of acid catalyst, this reaction takes place through partial S_N1 and partial S_N2 pathway. Epoxides are reactive, Epoxides get protonated followed by alcohol attacks to the stable carbocation and form the product.

Epoxides are reactive, methoxide ion attacks the Epoxides in a less sterically hindered position which forms the alkoxide ion, and then it gets proton from alcohol which form the product.

(f)

Interpretation Introduction

Interpretation:

The major product of given reaction should be given.

Concept introduction:

In the presence of acid catalyst, this reaction takes place through partial S_N1 and partial S_N2 pathway. Epoxides are reactive, Epoxides get protonated followed by alcohol attacks to the stable carbocation and form the product.

Epoxides are reactive, methoxide ion attacks the Epoxides in a less sterically hindered position which forms the alkoxide ion, and then it gets proton from alcohol which form the product.

(g)

Interpretation Introduction

Interpretation:

The major product should be identified.

Concept introduction:

Tosylation reaction:

The alcohol is treated with any tosyl chloride (methane sulfonyl chloride) which yields tosylated product this reaction is called as alkyl tosylate and which is shown below,

${\text{S}}_{\text{N}}\text{2}$ reaction:

The alcohols is reaction with acids like hydrochloric acid or hydrobromic acid, the bromine atom attacks back side of the carbon atoms which is bearing alcohol group which yield the corresponding inversion product.

(h)

Interpretation Introduction

Interpretation:

The major product of given reaction should be given.

Concept introduction:

Oxidation of alcohol:

Alcohols reaction with hypochlorous (oxidizing agent) in the presence of acetic acid which yields the corresponding aldehyde and ketones.

Primary alcohols gives aldehyde, secondary alcohols gives ketone.

(i)

Interpretation Introduction

Interpretation:

The major product should be identified.

Concept introduction:

Generally amines can’t undergo elimination reaction, therefore amines can be converted in to quartnary ammonium halide by treating with ethyl iodide in basic solution of potassium carbonate.

For elimination reaction quartnary ammonium halide can be converted in to quartnary ammonium hydroxide by using aqueous silver oxide.

Hofmann elimination:

Quartnary ammonium ion undergoes elimination when using strong base like hydroxide ion this reaction is called as hofmann elimination. Proton abstraction is takes place in β- carbon atom which is having more number of hydrogen.

(j)

Interpretation Introduction

Interpretation:

The major product should be identified.

Concept introduction:

${\text{S}}_{\text{N}}\text{1}$ reaction:

The alcohols is reaction with acids like hydrochloric acid or hydrobromic which yield the corresponding carbocation intermediate, this carbocation intermediate undergoes substitution reaction which yields the corresponding substitution product.

Tertiary alcohols undergo substitution very fast than the secondary alcohols because tertiary carbocation is more stable than the secondary carbocation than the primary carbocation.

Primary alcohol is less stable therefore it won’t undergoes ${\text{S}}_{\text{N}}\text{1}$ substitution reaction