nitration of benzene

Question 1

define electrophile

Answer 1

lone pair acceptor

full/positive partial charge

an atom or group that is attracted to an electron dense area

Question 2

define subsitution

Answer 2

when one group removed is substituted with another

Question 3

what reagents and conditions are needed to make the NO2+ electrophile

Answer 3

concentrated sulfuric acid and concentrated nitric acid (HNO3)

heat to 50 degrees C

Question 4

write the equations for the preparation of the NO2+ electrophile

Answer 4

H2SO4 + HNO3 ⇌
[H2NO3]+ + HSO4-

[H2NO3]+ ⇌ NO2+ +H2O

HSO4- + H+ → H2SO4

Question 5

give the evidence for delocalisation in benzene

Answer 5

• hydrogenation energies are lower than expected
• delocalised systems are highly saturated
• benzene is a flat molecule and all atoms are in the same plane (bond angle 120 degrees)
• when benzene is attached to an aliphatic skeleton it is called a phenyl group
• each carbon in benzene makes 3 bonds (the remaining electron of each carbon is shared with other atoms in ring. 6 electrons are delocalised around ring system giving stability)