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Benzene is a colourless, sweet smelling liquid at room temp.
It is highly flammable. p-orbitals combine
It is carcinogenic.
Shape = hexagonal C C
It is a component of crude oil. planar
Bond angle = 120°
Benzene has the formula C6H 6 C C
It consists of 6 carbons in a hexagonal, planar ring.
Each carbon is bonded to 1 hydrogen.
C C
Each carbon forms 3 covalent bonds, leaving 1 electron that is not
bonded.
This electron is in a p-orbital.
=6 These p-orbitals overlap to form a π delocalised system of electrons above
delocalised and below the plane of the hexagonal ring. This gives benzene its stability.
elctrons All carbon-carbon bond lengths are
Delocalisation def: intermediate in length between that of a
The π electrons are spread over several atoms. BENZENE single C-C and a double C=C.
The delocalisation of π electrons gives benzene greater than expected stability.
Alkenes readily undergo addition reactions whereas benzene doesn’t.
Electrophile - An ion or molecule that
Alkene Benzene Alkenes readily undergo electrophilic attacks regions of high electron density.
Add bromine Electrophilic No reaction addition reactions where Br2 and H2 act
water addition (Remains as electrophiles.
Orange to orange).
colourless
Hydrogenation H adds across Does not easily However, since benzene has a lower electron density because the
double bond - undergo electrons are delocalised they require a more powerful electrophile.
nickel addition This is why benzene will instead undergo electrophilic
catalyst reactions substitution reactions.
Benzene is a colourless, sweet smelling liquid at room temp.
It is highly flammable. p-orbitals combine
It is carcinogenic.
Shape = hexagonal C C
It is a component of crude oil. planar
Bond angle = 120°
Benzene has the formula C6H 6 C C
It consists of 6 carbons in a hexagonal, planar ring.
Each carbon is bonded to 1 hydrogen.
C C
Each carbon forms 3 covalent bonds, leaving 1 electron that is not
bonded.
This electron is in a p-orbital.
=6 These p-orbitals overlap to form a π delocalised system of electrons above
delocalised and below the plane of the hexagonal ring. This gives benzene its stability.
elctrons All carbon-carbon bond lengths are
Delocalisation def: intermediate in length between that of a
The π electrons are spread over several atoms. BENZENE single C-C and a double C=C.
The delocalisation of π electrons gives benzene greater than expected stability.
Alkenes readily undergo addition reactions whereas benzene doesn’t.
Electrophile - An ion or molecule that
Alkene Benzene Alkenes readily undergo electrophilic attacks regions of high electron density.
Add bromine Electrophilic No reaction addition reactions where Br2 and H2 act
water addition (Remains as electrophiles.
Orange to orange).
colourless
Hydrogenation H adds across Does not easily However, since benzene has a lower electron density because the
double bond - undergo electrons are delocalised they require a more powerful electrophile.
nickel addition This is why benzene will instead undergo electrophilic
catalyst reactions substitution reactions.
