Chapter 10.9, Problem 25P

(a)

Interpretation Introduction

Interpretation:

The given alkyl halide forms whether primarily substitution products, only elimination products, both substitution and elimination products, or no products when they react under the given conditions have to be explained.

Concept Introduction:

Elimination Reaction: It is just reverse reaction of addition where substituent from the given molecule is removed via E1 (the reaction depends only on the substrate involved in the reaction) or E2 (the reaction depends on both of the substituents in the reaction) mechanism. Elimination reaction of an alkyl halide results in the formation of an alkene.

S_N1 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.

S_N2 reactions take place in primary and secondary alkyl halides whereas S_N1 reactions takes place only in tertiary alky halide.

Tertiary alkyl halides undergo both E1 and E2 reactions whereas only E2 reactions take place in primary and secondary alkyl halides.

Carbocation: it is carbon ion that bears a positive charge on it. The increasing stability order of carbocation is as follows,

Primary carbocation < secondary carbocation < tertiary carbocation

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

(b)

Interpretation Introduction

Interpretation:

The given alkyl halide forms whether primarily substitution products, only elimination products, either substitution and elimination products, or no products when they react under the given conditions have to be explained.

Concept Introduction:

Elimination Reaction: It is just reverse reaction of addition where substituent from the given molecule is removed via E1 (the reaction depends only on the substrate involved in the reaction) or E2 (the reaction depends on both of the substituents in the reaction) mechanism. Elimination reaction of an alkyl halide results in the formation of an alkene.

S_N1 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.

S_N2 reactions take place in primary and secondary alkyl halides whereas S_N1 reactions takes place only in tertiary alky halide.

Tertiary alkyl halides undergo both E1 and E2 reactions whereas only E2 reactions take place in primary and secondary alkyl halides.

Carbocation: it is carbon ion that bears a positive charge on it. The increasing stability order of carbocation is as follows,

Primary carbocation < secondary carbocation < tertiary carbocation

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