KA 3: synthesis 3

Question 1

what is benzene (C6H6)?

Answer 1

the simplest member of the class of aromatic hydrocarbons

Question 2

describe the structure of the benzene ring

Answer 2

distinctive structural formula

Question 3

what is the stability of the benzene ring due to?

Answer 3

the delocalisation of electrons in the conjugated system

Question 4

what does the presence of delocalised electrons explain?

Answer 4

why the benzene ring does not take part in addition reactions

Question 5

what can bonding in benzene be described in terms of?

Answer 5

sp2 hybridisation, sigma and pi bonds, and electron delocalisation

Question 6

what’s a phenyl group?

Answer 6

a benzene ring in which one hydrogen atom has been substituted by another group

Question 7

what’s the formula of phenyl?

Answer 7

C6H5

Question 8

what can benzene rings take part in?

Answer 8

electrophilic substitution reactions

Question 9

list the reactions at benzene rings

Answer 9

halogenation=> by reaction of a halogen using aluminium chloride or iron(II) chloride for chlorination and aluminium bromide for bromination

alkylation=> by reaction of a haloalkane using aluminium chloride

nitration=> using concentrated sulfuric acid and concentrated nitric acid

sulfonation using concentrated sulfuric acid

Question 10

what is meant by “aromatic”?

Answer 10

describes any system containing a ring of atoms stabilised by pi electrons

Question 11

what is meant by “aliphatic”?

Answer 11

describes molecules with straight or branched carbon skeletons