Chapter 18, Problem 72PP

(a)

Interpretation Introduction

Interpretation:

Product formed when ortho-bromonitrobenzene reacts with sodium hydroxide at high temperature has to be drawn.

Concept Introduction:

Nucleophilic aromatic substitution reaction: $S_{N}Ar$ reaction is a substitution reaction occurs on an aromatic ring where a good leaving group on it is displaced by a nucleophile. During $S_{N}Ar$ reaction, a negatively charged intermediate called Meisenheimer complex is formed when a nucleophile attacks the carbon atom of aromatic ring.

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.

(b)

Interpretation Introduction

Interpretation:

Intermediate formed during the reaction between ortho-bromonitrobenzene and sodium hydroxide at high temperature has to be identified.

Concept Introduction:

Nucleophilic aromatic substitution reaction: $S_{N}Ar$ reaction is a substitution reaction occurs on an aromatic ring where a good leaving group on it is displaced by a nucleophile. During $S_{N}Ar$ reaction, a negatively charged intermediate called Meisenheimer complex is formed when a nucleophile attacks the carbon atom of aromatic ring.

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.

(c)

Interpretation Introduction

Interpretation:

Reaction that would takes place if the starting material is meta-bromonitrobenzene has to be given.

Concept Introduction:

Nucleophilic aromatic substitution reaction: $S_{N}Ar$ reaction is a substitution reaction occurs on an aromatic ring where a good leaving group on it is displaced by a nucleophile. During $S_{N}Ar$ reaction, a negatively charged intermediate called Meisenheimer complex is formed when a nucleophile attacks the carbon atom of aromatic ring.

Deactivators are electron withdrawing groups attached to the benzenes that have either positive charge or an atom with high electronegativity. They are meta directors.

Activators are electron donating groups attached to the benzenes that have either electron density that is able to push into benzene ring or a lone pair of electrons. They are ortho–para directing.

(d)

Interpretation Introduction

Interpretation:

Reaction that would takes place if the starting material is para-bromonitrobenzene has to be given.

Concept Introduction:

Nucleophilic aromatic substitution reaction: $S_{N}Ar$ reaction is a substitution reaction occurs on an aromatic ring where a good leaving group on it is displaced by a nucleophile. During $S_{N}Ar$ reaction, a negatively charged intermediate called Meisenheimer complex is formed when a nucleophile attacks the carbon atom of aromatic ring.

Deactivators are electron withdrawing groups attached to the benzenes that have either positive charge or an atom with high electronegativity. They are meta directors.

Activators are electron donating groups attached to the benzenes that have either electron density that is able to push into benzene ring or a lone pair of electrons. They are ortho–para directing.