benzene

Question 1

give 2 simularities between Kekule + delocalised benzene models

Answer 1

• both have overlapping p-orbitals
• both have delocalised pi bonds of e-s above + below the molecule

Question 2

give 1 difference between kekule + delocalised benzene models

Answer 2

kekule model has pairs of p-orbitals overlapping alternatively around molecule
WHEREAS
delocalised model has p-orbitals overlapping across all C-atoms- forming 1 delocalised bond system

Question 3

name the functional grp: NO2

Answer 3

nitro

Question 4

name the model kekule adapted his model to (alternating)

Answer 4

rapid equilibrium model

Question 5

give the 3 key faults with Kekule’s model

Answer 5

• benzene doesn’t readily undergo electrophilic addition (less reactive than would expect)
• hydrogenation enthalpy changes don’t match expectations- benzene H is less exothermic tha expected)
• bond lengths don’t match expectations

Question 6

name the 3 benzene ‘wrong-uns’

Answer 6

-benzoic acid (benzene + COOH)
-phenylamine (benzene+ NH2)
-benzaldehyde (benzene + CHO)

Question 7

give 4 arenes with stem-‘benzene’

Answer 7

-chlorobenzene (benzene + Cl)
-nitrobenzene(benzene+NO2)
-methylbenzene(benzene + CH3)
-chloromethylbenzene(benzene + CH2Cl)

Question 8

give 4 arenes with stem ‘phenyl’

Answer 8

-phenylamine(benzene + NH2)
-phenol(benzene + OH)
-phenylethanone(benzene + C=OCH3)
-phenylethene(benzene + CH=CH2)

Question 9

name the arene’s stem if benzene NOT the main functional grp

Answer 9

phenyl

Question 10

name the 2 benzene models

Answer 10

• kekule’s model
  -delocalised model