Electrolytic Conductance - Electrochemistry Video Lecture | Physical Chemistry

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having understood the metalic
conductance let's understand the
electrolyte ik conductance right so I
told conductivity of a solution of
electrolyte is called electron
acceleration conductance correct
conductivity of a electrolyte solution
is corn electrolytic conductors it is
caused by a movement of ions please know
n in class
CL minus ion so it is caused by movement
of miles the journey caused ferment of
ions ions are the critical thing here
earlier in the metalic conductance it
was electron which was they like current
courier here the ions are the current
carrier all right
so it is caused by the movement of ions
when they saw solution of electrolyte
under the influence of applied electric
potential difference for example and a
battery there is a potential difference
between these two is a potential little
bit in these two right because they are
connected now and with this the ions
will carry current good as I already
told conductance is inversely
proportional resistance so I can say
here also electrolytic conductance will
also be nothing but G will be nothing
but 1 by electro lighting resistance
that is R
correct so Ohm's law is true here also
Ohm's law is true hero so which we have
studied in physics so we know that V is
equal to IR right the Hans Klok this is
nothing but the electric potential
difference in volt since we are using in
chemistry II instead of volt we will use
G temp is equal to IR or it will be
equal to IR because we use electric
potential is IR right where I is the
current in R is the resistance here if
you want to find the resistance again I
don't R is nothing but Rho L Y the same
formula row is resistivity L is the
length is area so this L is what L is
the distance between two parallel plates
this is there and what is a a is the
nothing but area of cross section of the
solution which is in contact with
elector so this one is my a the one
which I have use only this much area of
the electrode is in contact with the
solution this is my correct so it is not
the area of the please note the a is not
the area of the whole electrode is the
area of only the electrode that is in
contact with the solution and draw we
know that is nothing but specific
resistance or resistivity right and
please note for any cell if you have
constructed as L by a will be constant
right because the length between these
two directors will be constant and this
aerial also be constant because it will
have fixed volume of solution so this L
by ay since it is a constant volume by
value L by ay and this constant for a
cell it is also called cell constant Y
because length and area is constant for
a given cell right so L Y will be
constant for a given cell it is also
called cell constant correct so the
other formula which we still into as
Kappa is equal to 1 by Rho this is also
true heroes please note if you have she
see the pure water it will have very
very low conductivity the
bulb may not glow also but if we
dissolve the electrolytes in this
example NaCl the bulb will grow the
conductivity increase so in this case
the conductivity depends on what the
nature of electrolytes obviously you see
if you add NSEL the most if you add weak
electrolyte example acetic acid the bulb
grows less right so I can say I can say
that the conductivity here also depends
on one the nature of electrolytes that
we have seen the next is the size of
ions to use why because here the ions
are the courrier right if I have any
plus I or I have ch3 Co - I am there is
a difference in the size so size of ions
produced is something is critical also
the nature of solvent by altering the
nature of solvent because if the solvent
is very viscous it is it is very thick
it will obstruct the flow of ions right
so viscosity of solvent also plays the
road fourth increase in temperature
please note here it's little different
scenario here so if we increase the
temperature what happens the mobility of
ions also includes right because see it
is here the ions are the courier you see
the one which is moving in the last
layer right the right dots which are
jumping in on either they are the
Careers the mobility of the ions also
increase and mobility the cations also
increased rate or the ions they increase
since the mobility of the ions increase
the conductivity also increase that is
one part second part increase the
temperature the viscosity of solution
decrease since the viscosity of solution
decrease the ions can move around easy
and thus conductivity also increase
correct so it depends on nature of
electrolyte size of ions nature of
solvent all and the temperature there's
a different ballgame here in the case of
metal conductance the metal conductance
is because of electrons so if we
increase the temperature seen both teams
are going to increase the temperature
the atoms move around here and there
right here the we have ions so they move
around here and there but since in the
case of metrology the atoms move around
here and there is difficult for
electrons to pass through so the moment
you heat a metal the conductivity
decrease but in case of this scenario
the moment you increase a temperature
the ions move around here and there and
here the temperature the conductance is
because of ions only and thus the
conductivity increase let's do a recap
of what we have said about the metalic
conductance and electrolytic conductance
so as I told in metal II conductance my
electrons are the career of current so
in this electrolytic conductance my ions
are the carrier occurring right the
metalic conductance happens in metal
under the influence of electric
potential difference obviously and this
happens in electrolytes under the gained
influence of electric potential
difference here the conductivity
decrease the increase in temperature I
have showed you why the conductivity
decrease with increasing temperature
because the atoms here moves around in
both case when you increase temperature
right implies atoms or ions they move
around move around and higher speed
correct now but in this case the moment
atoms move around the high estate since
the carrier is electron for electron is
difficult to pass through this high
speed moving atoms rise but in this case
the moment you heat the temperature the
atoms of ions move atoms or here we have
irons only sometimes near atoms also
because for weak electrolyte if you see
not all the atoms break
torian's right so that one's anions they
move around the high speed and but here
the carrier is Adams anion itself lines
it's the other career it's in the career
it's the carrier current carriers ions
itself so as we increase the temperature
the conductivity okay so they have
generally have high conductivity very
very high current you electrolytes only
have very low conductivity and the
moment if you use a metal for passing
electricity for long time you won't see
any difference in the metal metal will
be the same but if you use electrolytes
for passing electricity for a long time
you will see there is a change in the
electrolytes concentration especially we
used DC current at the regular it's
concentration may change this is
something we'll see in the next few
slides also you see the Nernst equation
also implies the same thing for a cell
the concentration change over a period
of time and here also since the same
electrolyte is used for a long time the
concentration will change and the
resistance in this case is due to
vibrating nuclei the vibrating atoms
here and here because it is electron
which has to pass through these peyote
nuclei but in this case the resistance
is due to ionic interaction viscosity of
the solvent and solvation of the solids
listen you got some another reason a
because the main difference in this is
electron this is the ions itself so that
is the difference between the metalic
conduction and electrolyte direction so
we have seen a lot of we have seen lot
of new terms resistance resistivity
conductance conductivity right let us do
a recap of all the SI units because
these are little critical for us right
so we have seen that resistance is Rho L
by that is one formula get to it right
so let's talk what do instance first he
noted by r and SI unit is ohm correct
you know means that they
but kgu meter square e square we don't
need this form 99 so SI unit is own just
focus on that and the and the formula is
r is equal to two low l by the next is
opposite of resistance that is
conductance noted by g there is nothing
but 1 by r and if you put the same
formula this becomes a ly row correct so
SI unit for this is Siemens s IE a mean
is denoted by s here we have ohms here
we have Siemens right this a CMS is
nothing but power on also called move
right this is what it is because
conductance is nothing but 1 by
resistance third we have resistivity
nothing but Rho this value Rho this is
also called specific resistance right
and this SI unit is omega we have seen
that vine because this is l by is
nothing but 1 by meter so you put this
side so this Rho becomes R into you see
it becomes R by L right find the unit
resistance is ohm is meter square and
lead lengths meter this gets cancelled
is becomes low meter so I say unit is
Rho meter right and rows centimeter is
also used so one row meter is nothing
one one row meter is nothing but 100 Rho
centimeter so both are use actually but
Rho meter is the SI unit so positive
resistivity is nothing but conductivity
there's nothing but kappa thank but one
by row right so it's SI unit is Siemens
per meter similar to this we have a row
meter here this is Siemens per meter
okay so conductivity of a material is
its conductance when it is one meter
long and it's cross-section is one meter
square but so if you want to see the
relation bit to here we have 100 Siemens
per meter is nothing but one even's
percent we we can do the math and see
why this right so that is all about the
four different terms we have seen
resistance conductance htat conductivity
and the SI units for these stubs because
these are essential to solve numerically
these are the common ones you see the
conductor sodium copper silver gold this
is the conductivity you talk about the
insulator connectivity is pretty less if
you talk about the aqueous solution
connectivity is there but you see the
units this is 10 to the power 3 this is
nothing right so compare these two they
are very very high also if you see the
conductivity of the solution depends on
similarity example in both case you have
h ec is the aqua solution but the
molarity is different the concentration
is different and they have different
conductivity semiconductor we have CU
silicon germanium so we wont shoddy much
about Sigma currently we have straight
is in the last chapter itself and glass
and all if you see the conductivity is
pretty bad and they are called
insulators almost they do not conduct
electricity but they told the unit of
conductivity is Siemens per meter that
connectivity thank you
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