Products of Electrolysis Video Lecture - NEET

alright then electrolysis well 4sl you
need to know one sort of electrolysis an
HL you need to know for other sorts of
electrolysis so the SL is just liquid
and 4hl dilute and concentrated sodium
chloride copper sulfate with graphite
electrodes which are inert and copper
sulfate with copper electrodes which are
not inert other ones you can work out if
you understand these right let me just
draw out a couple of electrolysis
equipments here so electrolysis means
putting in electricity the Power Packs
at the top Power Packs put electrons
where they don't want to go all right
then so positive electrodes and negative
electrodes they're just to remember take
the long one break it in two and that
makes a plus that's how you remember
that a long one is the positive
electrode alright let's start off with
dilute sodium chloride so each time you
have to write down the ions that are
present so those from the ionic compound
dissolved and H+ on o h minus from the
water looking at the positive ions
they're attracted to the negative
electrode by electrostatic attraction so
which one will be discharged
will I be making sodium or hydrogen well
you have to look at the standard
electrode potential list the lowest on
the list is discharged so remember that
the lowest on the list is discharged
here's the list and the lowest on the
list of one with the highest standard
electrode potential in other words is
hydrogen okay so I'm gonna be making
hydrogen at the negative electrode so it
picks up an electron from the negative
electrode it's gonna make hydrogen now
it's got to be h2 just balance that out
they're smashing
so the negative electrode is full of
electrons and hydrogens going to pick up
then from there looking at the negative
ions they're going to be attracted to
the positive electrode and this series
of discharges tells you which one's
going to be preferentially discharged Oh
H minus B CL minus and sulfate no one
knows what the hell that does I can't
even find it on the internet or my
friend or people that write textbooks no
one knows oh I did oh h- okay that wins
that's gonna make oxygen now this looks
like a horrible equation but it's it's
in the data booklet so you don't have to
memorize it as long as it's paper - so
the electrons are being pulled off the
Oh H - and pumped around to the negative
electrode electrons don't want to do
that they don't want to be pumped around
to the negative electrode well that's
what the battery does at the top the
power pack puts electrons or they don't
want to go I'll write them so if they
ask you for your observations what do
you see you can't say you see hydrogen
you have to say you see colorless
bubbles at each electrode alright then
concentrated sodium chloride once again
write out the ions h+ is still lowest on
the list and so i'm going to see
hydrogen there and Oh H - oh that makes
o - doesn't it no no I'm sorry if it's
concentrated then the more concentrated
one is discharged
so that means chloride is going to be
attracted to the positive electrode have
an electron ripped off I'm gonna make
chlorine gas what do you see green
bubbles let's look at the ones with
copper sulfate
so copper sulfate with inert electrodes
such as graphite or platinum and copper
sulfate with copper electrodes which are
not inert put in the charges on the
electrodes alright then so same as
before what's the lowest on the list
you know copper two-plus is lowest on
the list so that's going to be
preferentially discharged oh h- gonna
make oxygen that's pretty
straightforward just like the other ones
we saw so copper two-plus is gonna stick
on the negative electrode it's gonna be
plated on oxygen gas is gonna be
released at the positive electrode
alright let's look at the one with
active electrodes mmm it's not the same
this is a special case you just have to
learn so let's look at the electrolyte
the solution copper two-plus is
attracted to the negative electrode and
it gets copper plated so copper plates
on that electrode and on the positive
electrode copper turns to copper
two-plus OH
so one electrode gets bigger and one
gets smaller the next video in this
series explains this in more detail and
shows you the actual experiment you
might want to use the words reduction
and oxidation
now the color of that solution the
copper two-plus color is as ones being
added to the solution once being removed
so the color is going to remain the same