Aromatic chemistry

Question 1

Structure of benzene

Answer 1

6 C ring
C-C bonds are same length and have same bond energy
C6H6
p orbitals

Question 2

why is benzene stable

Answer 2

no C=C bonds

Question 3

which bonds are longer C-C or C=C

Answer 3

C-C

Question 4

why is benzene easily attacked by electophiles

Answer 4

due to the delocalised electrons

Question 5

evidence that benzene does not have C=C bonds

Answer 5

benzene’s hydrogenation enthalpy greater than if there was 1 C=C but less than if there were 3 C=C bonds

Question 6

nitration of benzene details

Answer 6

electrophilic substitution
concentrated nitric acid and conc. H2SO4
+NO4 electrophile
60 degrees C

Question 7

Freidel crafts acylation

Answer 7

benzene +acyl chloride —-> phenyl ketone + HCl
AlCl3 catalyst
reflux and 50 degrees C
electrophilic substitution

Question 8

formation of the electrophile equation

Answer 8

AlCl3 + CH3COCl —-> [CH3CO]+ + [AlCl4]-

Question 9

nitro group to amine group reagent

Answer 9

NO2- nitro group
NH2- amine

Sn and HCl reagent
Can be done with H2 and Ni catalyst
Heating
H2O formed

Question 10

Chlorobenzene properties

Answer 10

does not undergo usual substitution reactions as the delocalised electrons make the bond stronger

Question 11

phenol properties

Answer 11

delocalisation makes C-O bond stringer and O-H weaker
more acidic than an alcohol and does not oxidise

Question 12

phenylamine properties

Answer 12

less basic than normal amines
lone pair is less delocalised so less availble for accepting a proton