Chemical Properties of Benzene Video Lecture | Chemistry for JEE Main & Advanced

hello friends this video in hydrocarbon
par 26 a lot you buy exactly I call Lobo
fear from example it's not about the
chemical properties of arena so that is
generally follow electrophilic
substitution reactions and why
substitution because they are very
stable actually
these guys are stable even they have
double bond they are stable they could
give you resonance and other effects
which we have discussed in the past
chapter play as stable and since they're
stable rigidly go for electrophilic
substitution
they actually correct divide intervening
so this is they have double bonds right
you can attract the electrolytes this is
in lico for electrophilic reactions and
say they are stable so they really go
for some petition reaction by under
certain condition they also undergo
addition and oxidation
yes this is the reaction types we have
electrophilic substitution reaction
where we have nitro nitration
halogenation sulphonation little craft
alkylation reaction here in the clock
reaction and we have addition reactions
let's start the migration reaction this
is a addition addition sorry you should
be action where what happens is the
nitro group will replace a hydrogen
sorry here a nitro group will replace a
hydrogen this happens when you have
sulfuric acid and nitric acid then this
nitro group will replace a hydrogen here
and you get nitro benzene so let's see
the reaction mechanism here so I have a
nitric acid hno3 guy said H this is Miss
America so right then we are so with
this what they will form is water
molecule plus no.2 and this informal
English - correct now this water
molecule this is water actually plus
charge here is
Monica will go off and sleep so with
this I'll get what they know to class
and what polygons and odo Plus isn't
something like this
now let's react this no.2 bliss with
them Beansie this is my Benjy and this
is my Beijing and I have enough plus in
this match the plus chirps correct so
what will happen is and there is a
hydrogen here maybe some hydrogen is
hydrogen here - correct
so what will happen is I know - Plus
this electron this missile will attack
this correct this this hydrogen bond
will break and this will come on so with
this what you get is and this S Plus
will go will react with this thing and
we will get back - to us
correct see because of these no.2 class
this double bond is as my electrophilic
Center is litang this guy plus this
hydrogen bond so come here at remodel
break and then it will be a substitution
reaction let's understand the
halogenation reaction so this happens in
the presence of ladies I said like
ferric or aluminium salt of the halogen
machine learning so here the reaction is
you have a dream you have kept me there
should be a very high pressure you react
with some halogen you get Eddie in with
some collagen M hydrogen is out that is
the reaction we have so in this case
suppose there was a hydrogen here and
the chlorine will replace this hybrid
like you
you wondering what is the need of a else
here three here so alcl3 will make this
chlorine all the more electro fine the
mix showing more electrophile so the
reaction as I have it suppose I have CL
you have react with en CNG so this will
give me L plus n you get 4 minus this CL
plus you see is my strong electrified
all right now let's the reaction so
let's suppose I have a benzene here
that's being here where it's here this
is my so I have CL plus coming in so
what happen is this guy will attack here
correct this guy this bond will break as
negative and positive x key so in this
chlorine will attack in this car right
so what I will get is something like
this this is it attacked positive shot
you have a hydrogen and also close and
this is a stable compound because if you
see the resonance you can make more
structure of this right now what we'll
do we'll remove the hydrogenation from
this so what we do you remove this
hydrogen from this
for this we use this guy al same - the
same what this hydrogen from here so the
less it is be in your hold the chlorine
and this is my floor a bit correct and
with this if you see my HCl is out
pretty easy reaction nothing right here
so we'll talk about sulfonation reaction
here you see one hydrogen this is a
place this so3h true this happens in the
presence of concentrated sulfuric acid
it has to be fuming it has to be hard in
the gaseous phase 8 3 30 Kelvin
now the reaction is pretty like this you
have aromatic with hydrogen
you should get aromatic with so3h how is
this a three bond by loss of water from
h2 I suppose we wish to SM for so in
this we can get it suits me in h2 and
please don't it is a reversible process
and add something like this reversible
process okay so let's see the reaction
mechanism of this I have a benzene here
correctly just wear these things and
it's so3 you so treason this one like
this guy will attack this sulfur and
this bond break like this guy will tie
itself and bond will break so this will
be minus charge here B plus charge right
so this is the plus charge here
so what will happen is this bond if you
want to break it a break in the negative
and positive correct since plus so
you'll get something like this openness
and with a positive charge and other
bonds are intact
this is gone and this will be very slow
process its attack will be very slow
process so I have a hydrogen molecule
here awesome correct now what I can do
is I again lose one H from here right
that if I get a double bond will add
more stable to the system so I lose my
edge from here and I'll get my benzene
full benzene back this - and this s
which I am losing will go to this now
will get that ring back so this is my
final comma and that's
now let's take a friedel-crafts
alkylation reaction please known as
alkylation reaction so here we take
alkyne halides alkyl halide we react
with aromatic compound the presence of
Lewis acid Lewis acid you get something
like this you get cs3 good here did you
get Alki okay that this is an example
where you react benzene to CSD CL you
get tolling alright so here also a LC LC
the purpose of alcl3 is to increase the
electrophilicity of alkyl halide by
forming complex you can also use other
ladies as safe in handle be a 380 CL 2
ETA n CL do etc can also be used so
let's see the purpose of a s here
example IDL CL 3 here so reacts with
ch3cl so let me give you what it will
give you 3 H 3 + calm over time and will
be e LC + o - that's what do you correct
so now I have CH 3 plus volatile it
stings example and this benzene here I
have my CH 3 plus so this will attack
here since it was plus 84 minus 1 plus
this bond will break and you'll get
something like this H 3 and positive
charge it correct that you know so here
and these bonds will be done now what
happens is a positive charge here
there's a hydrogen here this hydrogen
will leave add that little form bond
here so what you'll get is in fact
benzene once again CSD and my expresses
are expressible because you my real self
omens
so what you get here is toning but easy
early so the only reason by using this
levers I said alcl3 is it'll increase
the electro Felicity on this create
cations vocals alright let's see a
citation reaction have little craft
oscillation reaction so here what we do
is here we have something they are H
form and we try to get a UH C oh right
so I have a benzene I react with assign
highlights here generally right is the
base again in the pins of alcl3
we get this is my assign winsy in this
case it is a seat open on all right
it is same same thing here also alcl3
will enhance the electrophilicity of a
sign halide exactly same as last one you
see here our cocl example i cs3 here
allison is to see well when you react
with alcl3 give ch3co plus and ALC and
for - correct so now this guy can easily
attack the benzene benzene alright and I
have ch3 sweet Oh
Plus this will attack here writes this
will break into minus and plus sign is
born so what you get is the very slow
process of actually so with this what
you get is this guy named 3c oh and this
is the plus sign here there is a
hydrogen here correct same thing this
hydrogen bond will break and form double
bond here this
ch3o
and this means and this is - tokino okay
very very similar reaction now I will
talk about addition reaction that is an
addition of hydrogen but since we know
that benzene is more stable than
cyclohexane is not easy process right it
has to be done under high pressure and
why because we know that this guy is
table in this guy is not very stable
cyclohexane so you need to add three
hydrogen in the presence of nickel and
it has to be very high in pressure and
similarly addition of halogens also
right so this is what you call benzene
hexachloride or we also call it lindane
and this is the insecticide in also you
have applied two molecules in the
business of sunlight but the very high
temperature because this is more stable
is this less thing thank you visit exam
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