L19 : Redox titration - Redox Reaction, Class 11 Video Lecture

hello friends this video on redox
reaction part 19 is brought to you by
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now let's understand a very critical
topic called titration we use this
pretty often in the labs dietitian is
nothing but the process of finding
strength of one solution against the
strength of already known solution right
or also using pH sensitive indicators
they call tight trains or type trainer
and you must have done something like
this in labs you have this pipe and you
have some solution here and some
solution here you keep dropping little
bit little bit and he mixing till the
color change right there is a Kachina
color that means endpoint and stage and
one reaction is complete and in that you
can tell that this reaction needs I mean
for example you have reaction of a plus
b c plus d can say that this milliliter
of and you have some let's suppose 10 ml
of a and then with reaction with
dropping little bit little bit you found
that the cv and this is a leaf suppose
and you you saw that you needed some xml
of v which you have observed then you
see that xml of B reacts with 10 ml ml B
because the moment the reaction is
complete the color changed because of
some indicators right we will talk about
this and then you say that okay if my X
ml of be required for let's suppose 10
ml of a then you can find the strength
of a right what is the percentage
strength or the kind of stuff you can
find you have done this kind of thing in
the laughs titration where you find the
strength of one solution say I am trying
to find the strength of solution B with
respect to strengthen soares a right and
the various types of titration the
acid-base titration drop titration gas
based titration complex geometric
titrations zeta put in here invitation
and many more but in this case we'll be
focusing more on redox titration because
that are chartered but before going
through redox titration let's also
discuss
acid-base titration and acid-base
titration that all depends on the mutual
of acid-base example in this case we use
indicators which have different colors
in a sleek and basic medium example myth
hi boil it it has yellow color and a
sleek medium and boil it color in basic
medium right methyl orange is red for an
aspic yellow in racing let muss is a
good test get it an acid blue in basic
right the Northlands color is nice and
pink in blue pink in basic so this kind
of titration where you have a acid-base
titration what we do is we react some
acid in base the moment it is I mean it
becomes neutral you get different color
at the moment it will mean a stinking
you get different color when you get
basic you get different color right so
with that you can find out whether the
reaction happened or not right so that
way this is used but in redox titration
it is little different so you see in
this case unknown concentration and
volume of pi train reacts with an ax let
determine the concentration here another
it is nothing but a substance which is
going under lashes wherein find the
percentage concentration of substance
and PI trend is nothing but my no one
region there they have known
concentration we know the concentration
of that so that n in the volumes of that
so that we can because I'm about
calibrating right so we know this
concentration of this so we can find our
concentration of this right this is
unknown and this is no that's the only
difference
so titrant is known and Tyrande
or annul it is something which is not
known and some of the popular type type
type or region in the market is all
these neutral in blue which is blue when
oxidizing then it's get reduced
it is colorless right or - el fin a
lemon which is violet in oxidizing and
it is renewable it's curls you don't
need to understand more because in your
class you won't have to
and this thing in detail but this
understand it's separation is a process
where you find the concentration of an
unknown solution by mixing with unknown
region various kinds acid-base redox and
acid-base where we take the privilege of
some indicators like medical phenoxy
lane or I mean their various indicators
which change color on acid and base but
in redox titration we perform our
titration and there we have indicators
which change color or oxidation and
reduction we oxidize it it changed color
a period user change color right we take
some examples for this and this is what
the redox in here I am talking about
right so there is t kisses in the redox
titration actually in the first case the
reagent which we used that itself is
color for example mno4 minus night they
serve a color for example island if you
oxidize and this mno4 is reduce the
color change a mana for - if you see
permanganate ion it's blue in color
a purple in color and this emitter - is
pink in color same thing with ironing ID
in this blue in color but when it
becomes I - I denying it is colorless
right so so the reagent itself is your
color the second scenario is the region
is able to oxidize the redox indicators
so I have relaunched indicators I have
told right so in case where my region
example if I am using CR 2 O 7 - 2 if I
am using this reagent right but this
reagent does not change color or
oxidation reduction but there are
indicators - example - Ln this will
change color the moment this is oxidize
or reduce right
so this can be used please note in this
case the reagent itself we change color
here the reagent is CR 2 goes in - -
they don't change color but they can
change color of the indicators the
moment they are read easily oxidized
right so that is also helpful to us
right the third is the reagents are not
even
the reagents which we are taking are
able to oxidize I - I see please note
here iodine is also used as a reagent
and iodine you also use indicator
because sometimes we use for example a
reagent which is let's suppose copper
copper is the region here right which is
used for reduction or oxidation and then
if copper can oxidize I am and assign it
will change the color of I - - I do that
is blue so we can use it okay see the
things are pretty clear the first thing
is the reagent is itself is colored the
second one is reagent is not changing
colored but really - Regents are able to
oxidize the redox indicator the third
you see is subpart of this I can make it
as 2.1 actually because this is same
actually but instead of using normal
adducts indicator we are using i - i and
this is a very cheap one I it is really
not because it is a very costly was
right so we use a lot in industry so
that's why we have covered this
spatially but this is part of this
actually there are two type only one is
with a reagent then self change color
for example mno4 minus i2 - the second
is the reagent don't change color by
three agents can change color of the
indicators right so indicators can be -
Amal I - also since I mentions used very
widely in the market and but this is
applicable only to those reagent because
not all the agents can oxidize I - and
they are some reagents which can oxidize
I'm ensign right so this is a subset of
this because not all reagents can here
motional reagents can oxidize a Xerox
indicators which we use that the most of
the redox indicators review almost all
the Regents are able to oxidize OC redox
indicators for example type in a fin
element but if you use I'm a design not
all the reagents will be able to
of oxidized I - I'm some of them can use
can oxidize so in that giving you the
cheaper alternative I - I and that's why
it is using the market so here they are
doing different thing one is it's
cheaper and second all nor not all the
reagents can oxidize this only few of
them can oxidize on I - line so if if a
region can oxidize I am enzymes way to
do you know I units and because it's
cheaper correct but they have some
limitation of the concept of oxidation
number and what is the limitation and
the limitation is pretty easy because we
have seen the redock the the concept of
redox reaction the concept of oxidation
definition itself is evolving right we
talked about addition of oxygen to Ock
addition of oxygen and removal of
hydrogen then we talked about addition
of electronegative and removal of
electro positive right and then we
talked about electron loss of electrons
then we talked about increase in
oxidation number increase in oxidation
number right increase in oxidation
number and then we talked about electron
density right so if you see a decrease
in electron density so the first light
which we took right a decrease in
electron density so if you see the
process the the definition of oxidation
itself is evolving it's changing and
that's the only limitation of oxidation
number because the definition itself is
not constant right every decade the
chemists come with a new definition that
we have seen this the history of
oxidation number initially they told
it's at the addition of oxygen they told
then they told addition of oxygen and
hydrogen then they told addition of
electro negative element removal of
electropositive element and then the
total loss of electronic oxidation then
they don't increase of oxidation numbers
oxidation and the current definition see
that decrease
hence it is oxidation thank you visit
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