3.3.10 Aromatic chemistry

Question 1

Nature of bonding in benzene

Answer 1

Planar structure
Intermediate bond length
Delocalised electron on each carbon

Question 2

Why is benzene more stable than cyclohex-1,3,5-triene

Answer 2

Benzene has delocalised p-electrons

Question 3

Why does substitution occur instead of addition reactions for benzene

Answer 3

Addition would involve breaking the delocalisation and losing that stability

Question 4

Arene melting points

Answer 4

High due to stability

Question 5

Arene melting points

Answer 5

Low as they are non polar and often cannot be dissolved in water

Question 6

Formation of NO2+ electrophile

Answer 6

H2SO4 + HNO3 –> H2NO3+ + HSO4-
H2NO3+ –> NO2+ + H2O

Overall:
H2SO4 + HNO3 –> HSO4- + NO2+ + H2O

Question 7

Electrophilic substitution electrophile

Answer 7

NO2+

Question 8

Formation of R-CO+ nucleophile

Answer 8

RCOCl + AlCl3 –> AlCl4- + R-CO+

Question 9

Friedel-Crafts Acylation catalyst

Answer 9

AlCl3

Question 10

What do the delocalised electrons in benzene act as in Friedel-Crafts Acylation

Answer 10

Nucleophile

Question 11

Reformation of catalyst in Friedel-Crafts Acylation

Answer 11

AlCl4- + H+ –> AlCl3 + HCl

Question 12

How to name molecules with benzene

Answer 12

Phenyl_______