aromatic compound

Question 1

delocalised vs kekule

Answer 1

.all bonds on benzene are the same length between the size of a single and double bond

.enthalpy change for hydrogenation is less exothermic than expected with it being -208

.more stable and less reactive

Question 2

naming benzene groups

Answer 2

NO2 = nitro benzene
COOH = benzoic acid
CHO = benzaldehyde
NH2 = phenylamine
alkyl branch longer than 6 = phenyl X
OH = phenol

Question 3

electrophillic sub of benzene mechanism

Answer 3

Br2 + FeBr3 —> FeBr4- + Br+

.arrow from benzene ring to Br+

.benzene ring with a positive charge and Br attached
.arrow from C-H bond to positive charge

.benzene with the electrophile attached (Br) anf H+

.H+ + FeBr4- —> HBr + FeBr3

Question 4

electrophillic sub of benzene with NO2 mechanism

Answer 4

HNO3 + H2SO4 —> HSO4- + H2NO3+

H2NO3+ —> H2O + NO2+

.same mechanism as the other

.H+ + HSO4 –> H2SO4

Question 5

benzene is less reactive than alkene

Answer 5

.benzene pi electrons are delocalised and alkenes pi electrons are localised

.= benzene has a lower electron density

.lower electron density = electrophiles less attracted = less reactive

Question 6

why is phenol more reactive than benzene

Answer 6

.the lone pair of electron on the O in the OH group is delocalised into the benzene ring = more electron dense = more susceptible to electrophillic attack

Question 7

phenol and bromine reaction

Answer 7

phenol + 3Br2 —> phenol with 3Br + 3HBr

Question 8

phenol + HNO3

Answer 8

phenol with NO2 on the 2,4,6C + H2O

Question 9

activating groups

Answer 9

OH
NHR
X
NH2
OR
R

.next group added is added to 2,4,6

Question 10

deactivating groups

Answer 10

.ketones
esters
SO3H
aldehyde
CA
CN
NO2
NR2+

.next group added is added to 3,5