Chapter 25 - Aromatic compounds Flashcards
What is the molecular formula of benzene?
C6H6
What is the Kekulé model?
Carbon atoms joined together with alternating double and single bonds
What are the three pieces of evidence that disproves the kekulé model?
Benzene does not take place in electrophilic addition reactions which alkenes do, all the bond lengths are between the length of single and double bonds and the enthalpy change of hydration of benzene is less negative than three double bonds.
Describe the structure of benzene?
Each carbon atom has a delocalised electron in a p orbital forming a ring of electron density and a system of pi-bonds
What groups are prefixes to benzene?
alkyl groups, halogens and nitro groups
When is the prefix phenyl used when naming benzene?
When the benzene ring is attached to an alkyl chain with a functional group or contains seven or more carbons
What does benzene and nitric acid form?
nitrobenzene
What catalyst and heat is used in forming nitrobenzene?
sulphuric acid at 50 degrees celsius
what type of reaction mechanism is the nitration of benzene?
electrophilic substitution
what happens if the temperature in the reaction between nitric acid and benzene is heated above 50°C?
further substitution reactions may occur leading to the production of dinitrobenzene
what is the electrophile in the nitration of benzene?
a nitronium ion
what is needed for the halogens react with benzene?
A halogen carrier
what is the reaction mechanism for the reaction between benzene and halogens?
electrophilic substitution
what would happen during bromination of the benzene ring?
One of the hydrogen atoms on the benzene ring is replaced by bromine atom
what is the alkylation of benzene?
The substitution of hydrogen atom in the benzene ring by an alkyl group