Aromatic

Question 1

Property of Jekyll’s structure

Answer 1

Cyclo-1,3,5-triene
Double bonds are shorter
C=C:0.135nm
C-C:0.147nm

Question 2

Evidence against Kekule structure

Answer 2

If benzene contained c=c then it would delocalise bromine water at room temp
Benzene has 6 equal bond lengths 0.139 nm

Question 3

Structure of benzene

Answer 3

C6H6 
Planar with 120 bond angles 
Bond length between C=C and C-C
Each c has one spare electron in P orbital 
Pi-ring above and below the ring
More stability

Question 4

How are pi-bonds formed

Answer 4

Over lap of adjacent p-orbitals

Question 5

NO2 group called ?

Answer 5

Nitro

Question 6

Benzene branch called ?

Answer 6

Phenyl

Question 7

Nitration of benzene

Answer 7

Conc H2SO4(catalyst)
Conc HNO3
Benzene (50-55)
Electro physics substitution

Question 8

Generation of NO2+

Answer 8

H2SO4 + HNO3 —> NO2+ + HSO4- + H2O

Question 9

Acylation of benzene

Answer 9

Acyl chloride RCOCl
AlCl3 catalyst
Electrophilic substitution

Question 10

Generation of Acyl electrophile

Answer 10

CH3COCl + AlCl3 —> CH3CO+ +AlCl4-

Question 11

Reaction of bromine with benzene and cyclohexene

Answer 11

Delocalised pi-ring has less polarising effect on electrophile as it is less electron dense

Question 12

Methyl group on cyclobenzene

Answer 12

Methyl group has a positive inductive affect increasing the electron density in benzene

Question 13

Uses of Nitrobenzene

Answer 13

Explosives

Question 14

Uses of phenyl amine

Answer 14

Dyes and pharmaceuticals

Question 15

Reduction of nitrobenzene

Answer 15

Tin and conc HCl

Makes phenyl amine + water