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Flashcards in Arenes Deck (21)
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1
Q

What are the 3 unusual things about benzene

A

It’s got delocalised structure

The molecule is planar

All 6 of its C-C bonds have the same length intermediate between single and double

2
Q

What gives benzene its stability

A

The delocalisation of electrons and its ring

3
Q

Describe the evidence that shows benzene stability

A

Cyclohexane when hydrogenated the enthaply change is 120

Benzene which is a triene should evolve 3 times this so the enthaply change should be 360

However it’s 208
360-208 = 152 showing benzene has a lower energy and this stability is due to delocalised ring structure

4
Q

What reactions does benzene undergo

A

Electrophilic substitution

5
Q

When benzene reacts with. Nitric and sulphuric acid what is formed and what is the reaction called

A

Nitro benzene is formed

Nitration

6
Q

What reagents are involved in nitration

A

Conc H2SO4 and HNO3

Reflux 50-55

7
Q

Give the equations for the formation of nitric acid in nitration

A

H2SO4+HNO3-> H2NO3(+) + HSO4-

H2NO3->H20+NO2+

8
Q

What is the catalyst in nitration

A

Sulphuric acid

9
Q

What is produced when benzene reacts with acyl chloride

A

Phenylketones

10
Q

What is the reaction called when benzene and acyl chloride react

A

Friedel-Crafts reaction

11
Q

Give the overall reaction in nitration

A

C6H6+HNO3-> C6H5NO2 +H2O

12
Q

Give the equation when alcl3 reacts with and acyl chloride in Friedal crafts

A

R-CO-CL +AlCL3->R-CO(+) + AlCl4 -

13
Q

Give the overall reaction in fridel crafts

A

C6H6+R-COCl->C6H5COR+HCL

14
Q

In Fridal crafts reaction what does the AlCl3 acts as

A

Catalyst

15
Q

What can Nitrobenzene be used to make

A

Phenylamine

16
Q

Give the reagents and the reaction name when nitrobenzene is converted to phenylamine

A

Reduction

SN(tin)
Concentrated HCl
Heating under reflux

17
Q

Why aren’t LiAlH4 and NABH4 used as reducing agents

A

As they give other products

18
Q

Give the overall reaction in the reduction of nitrobenzene

A

C6H5NO2+6[H]->C6H5NH2+2H2O

19
Q

What products are made from nitration of benzene

A

TNT

20
Q

What can phenylamine be used for

A

To make dye stuffs when it’s converted

21
Q

Why is it essential that the reaction temperature isn’t raised about 55 degrees in reactions with arenes

A

As further substitutions occur