Chapter 7.8, Problem 31PTS

(a)

Interpretation Introduction

Interpretation: The reaction mechanism and products for the given set of reactions should be identified.

Concept Introduction:

${\text{S}}_{\text{N}}\text{1}$ Reaction: It is a nucleophilic substitution reaction in which the rate determining step depends on one reactant. First step is the formation of more stable carbocation which is followed by the attack of nucleophile. Formation of more stable carbocation and the leaving group present in the substrate plays very important role in the reactivity of ${\text{S}}_{\text{N}}\text{1}$ reaction. The stability of carbocation is as the following order,

Primary carbocation < secondary carbocation < tertiary carbocation

Carbocation: it is carbon ion that bears a positive charge on it.

Chiral carbon: a carbon is said to be chiral if it is bonded to four different atoms in a molecule.

Leaving group: it is a fragment that leaves substrate with a pair of electrons via heterolytic bond cleavage.

Nucleophile: donates pair of electrons to positively charged substrate resulting in the formation of chemical bond.

Racemic mixture: It contains equal amounts of R and S isomers.

(b)

Interpretation Introduction

Interpretation: The reaction mechanism and products for the given set of reactions should be identified.

Concept Introduction:

${\text{S}}_{\text{N}}\text{1}$ Reaction: It is a nucleophilic substitution reaction in which the rate determining step depends on one reactant. First step is the formation of more stable carbocation which is followed by the attack of nucleophile. Formation of more stable carbocation and the leaving group present in the substrate plays very important role in the reactivity of ${\text{S}}_{\text{N}}\text{1}$ reaction. The stability of carbocation is as the following order,

Primary carbocation < secondary carbocation < tertiary carbocation

Carbocation: it is carbon ion that bears a positive charge on it.

Chiral carbon: a carbon is said to be chiral if it is bonded to four different atoms in a molecule.

Leaving group: it is a fragment that leaves substrate with a pair of electrons via heterolytic bond cleavage.

Nucleophile: donates pair of electrons to positively charged substrate resulting in the formation of chemical bond.

Racemic mixture: It contains equal amounts of R and S isomers.

(c)

Interpretation Introduction

Interpretation: The reaction mechanism and products for the given set of reactions should be identified.

Concept Introduction:

${\text{S}}_{\text{N}}\text{1}$ Reaction: It is a nucleophilic substitution reaction in which the rate determining step depends on one reactant. First step is the formation of more stable carbocation which is followed by the attack of nucleophile. Formation of more stable carbocation and the leaving group present in the substrate plays very important role in the reactivity of ${\text{S}}_{\text{N}}\text{1}$ reaction. The stability of carbocation is as the following order,

Primary carbocation < secondary carbocation < tertiary carbocation

Carbocation: it is carbon ion that bears a positive charge on it.

Chiral carbon: a carbon is said to be chiral if it is bonded to four different atoms in a molecule.

Leaving group: it is a fragment that leaves substrate with a pair of electrons via heterolytic bond cleavage.

Nucleophile: donates pair of electrons to positively charged substrate resulting in the formation of chemical bond.

Racemic mixture: It contains equal amounts of R and S isomers.

 (d)

Interpretation Introduction

Concept Introduction:

${\text{S}}_{\text{N}}2$Reaction: It is a nucleophilic substitution reaction in which the rate determining step depends on both of the molecules involved. The bond making and the bond breaking process happens simultaneously in this reaction.

Structure of the substrate plays major role in the reactivity of ${\text{S}}_{\text{N}}2$ reaction. If the substrate is more substituted then the rate of the reaction will becomes slower. Since the mechanism of ${\text{S}}_{\text{N}}2$ reaction proceeds through backside attack on the substrate, it depends on steric factor that if more groups attached near the leaving group the reactivity becomes slower. Hence, primary substrate favors ${\text{S}}_{\text{N}}2$ mechanism. The ${\text{S}}_{\text{N}}2$ reactivity increases in molecule with better leaving group and strong nucleophile.

(e)

Interpretation Introduction

Concept Introduction:

${\text{S}}_{\text{N}}2$Reaction: It is a nucleophilic substitution reaction in which the rate determining step depends on both of the molecules involved. The bond making and the bond breaking process happens simultaneously in this reaction.

Structure of the substrate plays major role in the reactivity of ${\text{S}}_{\text{N}}2$ reaction. If the substrate is more substituted then the rate of the reaction will becomes slower. Since the mechanism of ${\text{S}}_{\text{N}}2$ reaction proceeds through backside attack on the substrate, it depends on steric factor that if more groups attached near the leaving group the reactivity becomes slower. Hence, primary substrate favors ${\text{S}}_{\text{N}}2$ mechanism. The ${\text{S}}_{\text{N}}2$ reactivity increases in molecule with better leaving group and strong nucleophile.

(f)

Interpretation Introduction

Concept Introduction:

${\text{S}}_{\text{N}}2$Reaction: It is a nucleophilic substitution reaction in which the rate determining step depends on both of the molecules involved. The bond making and the bond breaking process happens simultaneously in this reaction.

Structure of the substrate plays major role in the reactivity of ${\text{S}}_{\text{N}}2$ reaction. If the substrate is more substituted then the rate of the reaction will becomes slower. Since the mechanism of ${\text{S}}_{\text{N}}2$ reaction proceeds through backside attack on the substrate, it depends on steric factor that if more groups attached near the leaving group the reactivity becomes slower. Hence, primary substrate favors ${\text{S}}_{\text{N}}2$ mechanism. The ${\text{S}}_{\text{N}}2$ reactivity increases in molecule with better leaving group and strong nucleophile.