L1 : Introduction - Redox Reaction, Class 11 Video Lecture

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reaction part 1 is brought you by exam
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objective of this lesson is to identify
the redox reactions as a class of
reaction in which oxidation and
reduction occur simultaneously we will
talk about oxidation reduction will also
define the term oxidation reduction
oxidant reductant
will explain the mechanism for redox
reaction in terms of electron transfer
process will also use the concept of
oxidation number to identify oxidant or
reductant in the reaction the classify a
redox reaction into combination reaction
decomposition reaction displacement
reaction and disproportionate reactions
they will find a comparative orders
Hmong various reactant reductant and
oxidant who is most powerful and will
learn how to balance a chemical reaction
using oxidation number and half reaction
methods will also learn the concepts of
redox reaction in terms of electrode
processes so the first question that
comes to our mind is what is it out
charge we must have heard of this term
oxidation and reduction and is
scientifically proven that whenever
there is oxidation there is a reduction
what does oxidation watch this reduction
will cover these things in the next two
slides and you know actually action if I
compare with the day to day life is
nothing but a person giving his person a
and person B plus and B giving money to
person a so in this case person B is
losing money right so let's suppose he
is giving one rupee or 10 rupee so the
person B is losing money and the person
is gaining money right
so same thing in a chemical reaction if
one element lose electron or one element
gained electron make the reaction the
net energy the red ma has conserved so
if one element is losing electrons
another element has to gain electron by
or someone has to gain electron so we
define the terms oxidation and reduction
based on the electrons lost or gained it
will go through a history of oxidation
reduction but this lie is just to show
that oxidation and reduction when it
oxidizes nothing but where we have both
oxidation reduction and oxidation
reduction now real life if you want to
compare that it is nothing but element a
or person a person B where person B is
giving money to person a so person B is
losing money and person a is gaining
money
the next question comes to our - why to
study redox reaction in that though
formally I have not defined the redox
reaction completely but and you must
have got some idea of reaction where we
have both oxidation and reduction called
redox reaction so the question is why
study redox reaction so if you see if
you talk about the metallurgy the whole
science of metallurgy where you create
or extract elements or metals out of
ores in that redox reaction is involved
if you talk about the purification of
metal there also purification of metals
like copper aluminium there also an
auction plays a critical role you see
the creation of soap or most of the
sandwich you use it happens through the
Nasri action see the working of battery
it works because the redox reaction
because a chemical reaction happens and
that is mostly the redox reaction you
see there the process of creating
medicines and all that involves it
actually actually if you see the trees
right the whole photosynthesis process
this is nothing what's a redox reaction
you see the car the burning of fuel is
also renounce reaction to cheap lot of
stuffs around us depicts redox reaction
so having say that since we have a huge
implication of or implementation of
redox reaction or they could rely it is
good that we understand what is
reduction reactions let's start with the
definition of oxidation the history of
the definition of oxidation as I told
redox reaction is something where you
have both oxidation and reduction taking
right this is what I told you just now
so what is the oxidation let us
understand the first understand the
history of oxidation so scientist in the
early area oxygen is plenty in Chile was
right we have a lot of oxygen we breathe
the oxygen anything you burn that means
oxygen so magnesium with for example
least the scientist burn in pod NGO
carbon they burn they got co2 so they
thought they gave the definition of
oxidation has nothing but addition of
oxygen to anyone this is please known
with a history this is not the current
definition this is the old definition
maybe in 80's or getting hundred into 70
hundred so here the old definition I do
not know the actual time is very old
definition scientists thought chemists
thought that oxidation is nothing but
the addition of oxygen that's why you
see the oxy word came right so if you
add oxygen to something you get
oxidation that time the reduction word
word was not even coined and then they
observe pretty more lot of other
experiments now what I call reaction
because chemistry science cue and
chemists cotopaxi to understand where
more reactions example if you see ch4
methane react with oxygen to get some
co2
also if you see s 2 s reacts with oxygen
to get sulphur so with these they found
that oxidation can also be
addition of oxygen or removal of
hydrogen why because in this reaction if
you see from s to s they have removed
hydrogen this guy has hydrogen is
removed right this becomes s itself and
this is also oxidation if you see right
so they expand the definition so earlier
they told oxidation is nothing but
addition of oxygen and then they told
more at spur with more reactions right
the understanding more reactions what
they told that oxidation is nothing but
addition of oxygen or renewable hydrogen
this thing was added because they wanted
to incorporate this kind of reactions
also so then the popular definition
became for oxidation you have oxidation
means addition of oxygen or removal of
hydrogen then again scientist analyzed
more and more equation for example this
equation my nation when reacted with
fluorine it got it gave MGF to now they
had the doubt whether it is oxidation
reduction watch video the current
definition says only addition of oxygen
or the new hydrogen so according to this
destination we are not able to define
this particular reaction correct because
in this equation I neither oxygen is
involved or not hides me in form so but
if you see oxygen is what electro
negative element and hydrogen is one
generally h plus electro positive
correct so oxygen is my electronegative
element and hydrogen is electro positive
so what they did they have increased the
scope so they told that instead of
addition of oxygen itself they told
addition of any electronegative element
and removal of our capital n yeah
removal of hydrogenation of hydrogen the
door any electro positive you see like
this so they increase the definition or
they have increased the domain of
oxidation they told that instead of
addition of oxygen or removal of
hydrogen oxygen is electronegative
element so addition of any
electronegative element hydrogen was
electric
development they don't removal of a
electro puzzle so the new definition
that became popular in fact we have
better definition now for oxidation is
that you oxidation is the Connells or
removal of electro positive elements
like hydrogen sodium sulfur like that or
addition of electronegative element like
oxygen fluorine chlorine correct then
they have more def experiments example
sodium reacts with sulfur given a to s
now in this case if you see they also
absorb that in this case sodium was zero
power and this becomes na 2 s that is
this plus 1 power so if you see in this
case sodium becames
sodium glass and it lost from the
electron so the new definition became
oxidation is nothing but loss of
electric current so if you see in this
case sodium na s solid becomes na plus
this is in the class you get to both
side because this equation has n into
here right to na plus so if you see in
this case sodium becomes sodium plus by
losing one electron so the new
definition became oxidation is nothing
but loss of electron and the reduction
is nothing but gain of electrons oxygen
but the opposite of this so I am just
covering the oxidation now so I am just
focusing on oxidation part
correct so the new definition became
oxidation of loss of a little because
they studied not a lot of other
experiment equations reactions and they
found that that has more proctoring
definition for oxidation the new
definition came after this that is
oxidation is nothing but increase of
oxidation number so we will define what
is oxidation number so that your
constant will be clear in the next few
slides what is oxidation number
right and after that the latest
definition says that oxidation nothing
but decrease in electron density this is
the latest definition but we will stick
to more of these two definitions this
definition right I the loss of
electronic ease of oxidation number it
means all the same but this is more
popular so increase of oxidation number
is something we shall stick to but these
were there this way all historical
actually went yeah it is good to
understand how the definition of
oxidation got evolved from addition of
oxygen to addition of oxygen and removal
hydrogen to addition of electronegative
element removal of electropositive
element to loss of electrons to increase
of oxidation number to decrease in
electron density so the definition
evolved thank you visit exam viacom to
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