Aromatic chemistry

Question 1

Explain why benzene typically undergoes substitution reactions rather than addition reactions (1)

Answer 1

They are able to retain the delocalised ring of electrons

Question 2

Outline the conditions when converting NO2 group to an NH2 group on a benzene ring (2)

Answer 2

Tin / Sn, concn HCl and heat under reflux
Add NaOH

Question 3

Outline the reactions that form the NO2 (+) electrophile from HNO3 and H2SO4 (1)

Answer 3

HNO3 + H2SO4 —> H2NO3(+) + HSO4(-)
H2NO3(+) —> NO2(+) + H2O

Question 4

Describe the mechanism when reacting the NO2 electrophile with benzene (3)

Answer 4

Arrow from benzene ring to NO2(+) group
Arrow from H bond to positively charged benzene ring
Correct intermediate with horseshoe ring and +ve charge