Battery Primary: Leclanche Cell (Part - 31) - Electrochemistry, Chemistry, Class 12 Video Lecture

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exam now let's start the very critical
topic called batteries what are the
batteries batteries are galvanic cells
or set of the ilanic cells connected in
series and we can use them for source of
electrical energy correct and they are
nothing but set of galvanic cell in
series they're connected in series and
we use them as source of power in our
home and in all these jelly chemical
energy is converted into electrical
right example in our laptops my Mobile's
in my clocks inverter this is in my car
all these places we used this battery
like their two type of battery actually
they are primary battery and secondary
battery so before we even go through the
types of battery let's see one other
vest list what do we want in metals when
you buy battery usually by four towers
four laptops so what badly to be a
practical use in our day-to-day life it
should be light tsunami very heavy it
should be compact you can carry it it's
more this should not drop during its use
it's not either when I bought this
battery it was too old and after one
month became 1.5 volt right because that
is the electronic device where I'm
connecting this battery to will not work
it should be rechargeable if possible it
should last longer by I should not buy I
mean I should not keep changing the
battery daily if I just fix a battery it
should work at least for a year or six
months it should be less it should
create less in mom in pollution jelly
batteries if you see there they have
chemicals and these chemicals also
create in Amman pollution so you want
these batteries to be in mom and
friendly right and also it should be
easy disposable it's not Elijah's board
the battery
I want to despoil it I can't dispose it
should not be very poisonous it should
be something which can easily be
disposed these are the basic wishlist
that we are looking for in a given
battle example when you buy a
lithium-ion battery it helped almost all
these features when you buy a battery
from a boss it has almost all the
features except at the rechargeable part
we buy the battle for the inverters or
the battery which we use in a car the
lead battery actually there's a red
battery will discuss more about these it
has almost all the features that we are
looking for so depending on the type of
requirement whether you want
rechargeable or not or what is the size
of by free you are looking for we have
different kind of batteries in the
market hey there's a toll there two
different type of battle its primary
battery and secondary batteries so
primary batteries are generally is an
introduced primary single use a single
use battle there is use and throw use it
once it is dead dispose it right for
example the batteries which is using
clocks watches calculators we use
primary battle secondary batteries are
rechargeable batteries you can use a
second time right rechargeable they are
rechargeable battery right example
latest batteries lithium ion batteries
that is using mobile phones laptops they
are all rechargeable batteries you can
recharge them again in Turkey let's
understand the skin apart missing
details right the primary batteries so
let's see the primary batteries so they
are batteries which are used one use
once right and once it is dead fluid or
disposal they cannot be recharged they
cannot be recharged
correct so in this electrochemical
reaction whatever is happening in this
batteries are irreversible reaction they
are not reversible to action so initial
cost is less for these batteries initial
cost is less generally whether you buy
for the clogs on the watch or the tache
these are all
the non-dischargeable battery primary
battery the initial cost is less as
compared to chicken to battery right and
these are useful when long period of
storage is required you keep this
battery for a long time then use it
either the duration of the storage is
more and the application which is
required small amount of current small
amount of current or longer time current
for longer time so here time is more it
lasts for longer but the amount of
current gives us less right so a good
example of this is leclanche SL and they
are invented this way is invented by the
French scientist George leclanche in
1866 right so in this case what he did
was he replaced the carbon electrode
which was there in the furry it replaced
a copper electrode which was there in
the governing cell with carbon in
governing sir that's what he did in 1866
my clan chat will study in detail about
this cell now since I've told this was
moving by jaws I climbed it is 66 this
is how it looks 3d view say if you see
what is here in this is this is a carbon
and this is positive charge and this is
my negative charge correct this is jink
as usual you have not replaced the Jing
only copper heather is placed with
carbon and typically this is my glass
you see is a glass here and this is my
porous pot or a spot I'll tell you why
it is used and here we have this
powdered magnesium
the exile powder domenico then it also
has some granulated carbon late this is
jelly used to prevent polarization and
right here they went polarization and
discuss about this also correct and then
we have here we have the pink one is the
saturated aqua solution of ammonium
chloride nh4cl so in the real time you
see nh4cl it is colorless as we age as
shown pink here this nh4cl and that's
all correct so if you see this carbon
rod this is in a porous pot and this has
this powdered mno2 right so here my
electrolyte is NS gaussian that is my
electrolyte so let me write it here this
is my electrolyte and my electrodes are
carbon and zinc two electrodes right and
this mouth of this whole jar is sealed
it is actually sealed you see the whole
thing is sealed with a pitch there's a
pitch here it is sealed with the pitch
so that the nh4cl should not come out of
the jar correct and please not a nice
forest for seal is a very strong
electrolyte well let's see the reaction
happening see this has nh4cl we know the
nh4cl is a very strong electrolyte so
nh4cl will immediately break into NH 4
plus and Cl ends right there will be a
lot of NH 4 plus and Cl minus ions here
so I will put some CL minus CL minus
right CL minus 3 CL minus and 3 NH four
plus
okay so we have CL minus CL minus is
going to CL minus we have and we have so
many NH 4 plus now if you see Zink has
tendency to lose electron correct we
have seen that Zink wants to go to Zn
plus 2 plus 2 so what zinc will do zinc
will combine with the CL minus here it
will become Jayden CL 2 and this it'll
lose two electrons correct now that
means the electrons here because zinc
has reacted with chlorine and become
Jaden CL 2 and the JNC end will be
somewhere here only but there are two
electrons here more zinc will react and
more two electrons will come so
similarly like this will have more
electrons here since they are more
electrons in this electrode this
electrode becomes negative charge the
zinc electrode becomes negative charge
now NH 4 class it moves to carbon Don
this is the poorest one it can move to
carbon all right so now NH 4 plus we'll
take electron from this carbon rod and
will become nh3 and if you see some
hydrogen gases involved so with this
there is a deficit of electron here in
this carbon carbon become positive
charge so micelle will go now again
since they are lot of hydrogen here
because the reaction is happening here
right if more hydrogen comes here then
polarization will happen because this
electrodes will absorb this hydrogen
right
and with this polarization the battery
will not work properly so we want to
avoid this polarization
correct so what we do is we use MNA -
this hydrogen gas whatever is there will
be oxidized by mno2 so hydrogen gas if
you see when mno2 reacts with this it
forms a bit of water and mn 2 O 3 way it
gets oxidized and thus polarization is
provided if you see the role of mn2 was
only to prevent proliferation that's all
so pretty easy equation I have nh4cl it
easily breaks into NH 4 plus in
sino-asia
the CL minus comes near contact with
zinc and they react zinc become zero n
plus 2 this reaction happens Inge will
see her - it again becomes 0 CL 2 + 2
electrons released so this zinc
electrode has lots of electrons it gets
negative charge when connected to the
circuit with the circuit now it needs
the deficiency of electrons here how so
how it is done is ammonia NH 4 class
comes this side react in this carbon
side right
it gets the electron from this carbon
because the moment you connect with a
circuit right you get the electronically
electron flows the same electron is
flowing through the circuit and let's
suppose there is a bulb here it glows
right same electron comes it comes here
by the circuit and this electrons are
used by NH 4 plus now to give ammonia
and hydrogen gas and then this hydrogen
gas will create polarization and this
hydrogen gas may be absorbed by this
carbon electrode and this may not work
properly so we have this amino - so what
amino do will do it will react with his
hydrogen gas and recover this - water
and will prevent polarization correct
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