Aromatics ( Benzene )

Question 1

What was kekules structure called

Answer 1

Cyclohexa-13,5 -triene

Question 2

3 ways to prove kekules model wrong

Answer 2

Hydrogenation, reaction with Br2 and bond lengths

Question 3

Reactivity with Br2

Answer 3

No double bonds so doesn’t decolourise bromine water

Question 4

Hydrogenation of benzene

Answer 4

( when u get rid of C=C which requires-120kj mol-1 of energy so expected -360kjmol-1) but -208 actually used. 152 more stable due to rung of delocalised electrons.

Question 5

Bond lengths

Answer 5

C=C bonds are shorter than C-C bonds. C-c bonds are of equal lengths in benzene in X - ray crystallography

Question 6

Structure of benzene

Answer 6

Hexagonal planar with 120 degree angle
Molecular formula of C6H6
Delocalised electrons in p orbitals which overlap side by side and form an extended pi sustenance. The delocalised electrons move around forming ring of delocalised electrons

Question 7

Nitration.

Answer 7

50 degree using water baths
H2SO4 as a catalyst
Uses are dyes, explosives, pesticides

Question 8

Forming the electriophile NO+

Answer 8

1. H2SO4 donates a proton to HNO3 HNO3+H204=H2N03+ + HS04-
2. Protonated nitric acid losses a water molecule to form NO2+ which is the electrophile
   H2NO3+=H20+NO2+

Question 9

Formation of the catalyst for nitration

Answer 9

H+ + HSO4- (from forming electrophile) = H2SO4 ( catalyst)

Question 10

Freidel- craft acylation

Answer 10

CH3C|+A|CI3=C+H3 + AlCI4-

Question 11

Forming the original halogen carrier with halogen Hallide

Answer 11

H+ + AICI4-=АСІ3+HCl