A2 things to learn Flashcards Preview

Chemistry > A2 things to learn > Flashcards

Flashcards in A2 things to learn Deck (22)
Loading flashcards...
1
Q

three bits of evidence against kekules benzene

A
  • doesnt easily undergo electrophilic addition
  • bond length of all bonds is the same when it should be three sigma and three pi
  • enthalpy of hyrdogenation is less than expected
2
Q

what are the reagents and conditions for the halogenation of benzene

A

Cl and halogen carrier (catalyst)

FeCL3 or AlCl3

3
Q

reagents for nitration of benzene

A

conc. nitric acid and conc. sulphuric acid (catalysts)

4
Q

what does freidel-crafts allow you to do?

A

add carbon chains to benzene rings

5
Q

alkylation using a haloalkane, what do you do

A

where the halogen is, add the benzene ring and make the halogen bond with the lost H

6
Q

alkylation with an acylchloride, what do you do

A

where the halogen is, add the benzene ring and make the halogen bond with the lost H

7
Q

why is phenol more electron dense than benzene?

A

there is a LONE PAIR in the P ORBITAL OF THE OXYGEN that overlaps with the p orbital in benzene so the electrons are PARTIALLY DELOCALISED INTO THE RING

8
Q

how does phenol react with bromine (aq)

A

no catalyst needed (halogen carrier)
so easy multiple substitutions occur
it happens on carbons 2, 3 and 6

9
Q

how does phenol react with nitric acid

A

no catalyst

forms a mix of 2-nitrophenol and 4-nitrophenol

10
Q

how does phenol react with water?

A

it partially dissolves because the OH can make hydrogen bonds but the benzene ring can only make induced dipole-dipole interactions

it also forms a weak acid, more strong than aliphatic alcohols because the ring weakens the OH bond and makes it easier to lose the H

11
Q

how does phenol react with sodium hydroxide

A

it forms a salt: C6H5O-Na+ (aq)

12
Q

how does phenol react with sodium

A

it forms an ionic salt: C6H5O-Na+ (s)

13
Q

how does it react with metal carbonates

A

IT DOES NOT
it is a way to distinguish phenol from carboxylic acids
they both react with sodium and sodium hydroxide but phenol doesn’t react with metal carbonates

14
Q

in phenol what carbons do things substitute on to

A

2 4 6

15
Q

in a benzene with an NH2 group what carbons do things substitute to

A

2 4 6

16
Q

for benzene with a NO2 where does substitution occur

A

3 5

17
Q

arrangement of pi electrons in benzene

A

in a ring, delocalised between the six carbons above and below

18
Q

arrangement of pi electrons in phenol

A

2 extra pi electrons from the O in the OH are part of the delocalised electrons

19
Q

how to work out a haloalkane + any kind of amine?

A

basically replace one of the Hs with the alkane and put that with the H to make like HCl or HBr or whatever

each progressive stage of amines has less Hs

20
Q

how does one [b]rocure an aromatic amine?

A

reduction of nitroamines such as nitro benzene

21
Q

reducing agents needed for aromatic amine production?

A

tin and conc. HCL

22
Q

conditions for making aromatic amines

A

100 degrees C under reflux and 30 mins in a strong alkali to neutrakise the acid