Video: Adsorption and Absorption Video Lecture - JEE

hello friends this video on surface
chemistry part 2 is brought to you by
exam fear calm
no more fear from exam again I will give
you some examples of adsorption in our
day-to-day life the first example is
same in the morning you are all dressed
up your skin is to be clean you go out
for play and you play cricket basketball
whatever you want or you go to school or
you would opinion market by the time you
come back your face is dirty your face
is dirty because the dirt has been
adsorbed dirt adsorb on skin surface
correct dirt has not got gone inside
your blood but it's only on the skin
surface and that is a good example of
adsorption so here I have a coding spin
I'll see how it behaves when I use paper
or plastic on one side or tissue paper
on the other side right if you see here
is all holding spilled this is a tissue
on the left hand side tissue paper
plastic sheet on the right hand side if
you see the left hand side the whole
thing is adsorbed rights if you see the
whole bouldering is absorbed in this
tissue but on the right hand side the
coating is adsorbed only on the surface
if you have seen this example so this is
the one good example of the surface
chemistry so here coating is adsorbed on
the plastic surface here the coating is
totally absorbed by the tissue paper
another good example of adsorption is
water on the leaves so if you see here
sometimes or sometimes in the winter or
the foggy season the water gets adsorbed
on the lips you see water gets adsorbed
if you just a sec this leave the water
will follow or if you just wipe this
leaf with the cloth it will become dry
that is why because it is adsorb it is
not absorbed right hope you understand a
little absorption and absorption the
next good example of adsorption is
chocked dip in the ink so if you have
the chocolate suppose this is a chalk
here you dip this in an ink
maybe for five minutes not cool
you take this out and you cut this and
write this see this cross-section this
cross-section
try to see this cross-section if you'll
see this cross-section you see the and
this is something like this so you see
what happens is this is my ink and this
will remain solvent because my ink is in
water so you see the whole chalk is wet
but the ink is only in this layer
because ink is adsorb by this chalk but
when you talk about the water water is
absorbed another shot you see this is a
good example where both are happening
the ink is getting adsorbed because ink
is only on the surface of the chalk
water is getting absorbed because the
water is in the whole chalk it's a very
good example of a scenario where would
adsorption and absorption take place and
you can actually visualize it you can do
it in your home pretty the experiment so
before now to understand this term
adsorption and absorption in a little
detail manner it's good to introduce two
terms is bulk and surface so what is
bulk never I said see for any object you
take for example tomato gold coin gold
of biscuit or this sponge or water
anything you take this part which is
exposed to another state for example it
is a solid is exposed to my air this
part is all my surface but inside this
whatever you have is bulk example this
to my to the red part is or my surface
but if you just break this tomato
whatever get you get inside this inside
this if you see you will get double its
seeds also inside this those things
forms bulk here also if you see the
record spawned this part is exposed to
air right all this this is nothing but
my cuboid so all the six surface 1 2 3 4
5 6 6 surface is my surface you call the
surface and whatever is inside is my pal
in this water also able to see this part
is my surface right because in with this
part is covered with the glass so no
reaction will happen from here only this
part is my exposed surface and whatever
inside this is my bulb so very in
critical down bulk and surface and we'll
be using these terms to explain the
definition of adsorption and absorption
right so let's define this term called
adsorption adsorption T as I have told
the surface of solids or liquids they
have this tendency to attract and retain
molecules with which it comes to contact
for example this surface this is my
surface this is a tendency to attract
attract and retain molecules with which
it comes in contact and these molecules
remains only on the surface and it does
not go deeper in into the bulk so if you
see example dirt
or dust will retain only on the surface
it will not go inside the gold if you
watch this the dirt will go right to the
this anything dust or for example
nitrogen gas hydrogen gas will be only
on the surface do not go inside the bulk
right so thus this is something we
should know this is natural phenomena so
this natural phenomena that is this
national phenomenon that is nothing but
a combination of molecular species and
the surface rather than at the bulk the
solid is called
adsorption for example in this case this
is my activated charcoal this is not a
molecule of Ed accurate chopper this is
the whole one piece of activated
charcoal if we draw this in the square
form you should survive all right this
is one piece of activated charcoal now
this activated charcoal has a surface
please no this is not activated charcoal
molecule this is hold activated charcoal
I am talking about right
this activated charcoal now one piece of
activated charcoal actually this
activated charcoal has a tendency to
adsorb gases so if you see these are the
gas molecules and these gas molecules
are being adsorbed on the surface of
activated charcoal this we see this is a
surface of activated charcoal correct
this is not this is activated charcoal
please let me write it this is not
activated charcoal molecule it's a one
activated charcoal and we'll see this
activated charcoal a lot in our next few
slides now so we have two different
terms the molecule species for example
dust gases or something that accumulates
on the surface they are called adsorbate
for example here the gases is mine
adsorbate because these are something
that gets accumulated on the surface
right and this material on the surface
of which adsorption take place is called
adsorbent so here my activated charcoal
is ad zorb and
so hope unasyn a difference adsorbent is
the molecules the gases which get and
solved
adsorbent is the surface on which
adsorption tables for example this gold
here also if the dirt particles get
adsorbed so this third particle will be
my adsorbate and this is gold so gold is
a surface on which everything is
happening so gold is my adsorbent please
know once again adsorption is a surface
phenomena let me repeat once again this
is a surface phenomena this happens only
on them
on the other server so to make this
adsorption more effective what we do is
we increase have to include the surface
area because adsorption of the surface
phenomena and we can do this by breaking
it into small particles in fact we will
see one numerical also in this so if you
see if you have one cuboid it settles
right it has some surface area now if
you break this cuboid in great shape 100
piece hundred piece if you break the
small small keywords something like this
what will happen you see that eventually
you will end up increasing the surface
area we will see one numerical where
we'll have this maths and with math
we'll see the surface area has increased
in fact you can do this on your own also
so between since this adsorption is a
surface phenomena right we can say that
adsorption is totally dependent on
surface area correct so to increase the
adsorption we have to increase the
surface area to increase the surface
area what we can do we can actually
break into small pieces for example this
char pool right because charcoal is a
good and Zoar Bend
circle is a good absorbent so we
generally break sharpened into small
piece or the silica gel which is used
for sucking the moisture from the carton
box or alumina gel the clay or thus
collides they are finely divided
examples of adsorbent and why if you see
now let's suppose this is my big piece
of charcoal right this is my little big
piece of charcoal correct now this big
piece of charcoal and then I break this
into swans one piece like this this may
involve the same chocolate things broke
into small valleys maybe it will have
more correct what's one looks like this
now you see this big piece of charcoal
can absorb these many molecules because
the molecules are getting adsorbed on
the surface right as I've told this is
my activities our core piece right now
if you break this if you see the more
and more molecules can get absorbed
right if you see the green ones are my
gas molecules the blue one is my
charcoal activated charcoal and we see
can you just visualize this I'm just
drawing it the more and more gas
molecules will be heads off I hope you
got the concept I need not draw more but
you see here more and more gas molecules
are getting it why below services more
weights when you break this into more
pieces the surface area is more and
since this adsorption is just a surface
phenomenon right the more you take the
surface area the more is the absorption
and that is the reason why we break a
particular substance small piece because
the moment you bring in too small and
this is all three three-dimensional I'm
just drawing it looks like a circle
which is actually is spherical in shape
or something of that sort all three
dimension with all three dimension
because activity Arkell is actually a
three-dimensional piece will show you a
picture of chocolate the next few slides
so that is all about the adsorption so I
Dawkins one accumulation of molecular
species at the surface rather than at
the bulk of the solid is called
adsorption since it's a surface
phenomena to increase the absorption we
have to increase surface area and this
can be done by breaking a particular
substance into small piece because the
moment you break apart you as a change
is one piece the surface area equals
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