Hydrogen Bonding Video Lecture | Physical Chemistry for NEET

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before watching the video please make
sure you have watched part 1.30 let's
talk about hydrogen bond hi personal
bond is nothing but attractive force
which binds hydrogen atom of one
molecule with electronegative atom and
when I say electronegative atom I mean
she items it should be either fluorine
oxygen or nitrogen example you have this
HF for it is highly electronegative it
in little partial negative charge here
hydrogen is electro positive part
positive charge because fluorine
attracts electrons towards itself so and
then what will happen is this is my HF
now this hydrogen says it has slightly
positive charge it will be binding with
the next fluorine atoms this is called
hydrogen bomb we will study hydrogen
bond and more detail in the next chapter
we will study the msre this module force
is the type of wonder what for actually
which binds two molecules right so here
we see hydrogen bond acts as a bridge
between two atoms there are two atoms
they are either two atoms and there hold
and this hydrogen bond has a bridge
why we have hydrogen bond so molecules
it has high that contains a highly
electronegative atom linked to a
hydrogen atom in that case we have a
hydrogen bond and the size of the
electronegative atoms be very small so
that's why only fluorine nitrogen oxygen
can form hydrogen bond because they are
electronegative plus their size is small
so please not only fluorine hydrogen
oxygen forms hydrogen bomb with a
molecule in in a molecule which has
hydrogen atom and one on these atoms
chlorine nitrogen oxygen there are two
types of hydrogen bond intermolecular
and intramolecular so if you want to
understand the difference let's
understand the word internet and
internet so we talk about Internet and
you will not work internet then you say
internet you can everything you can see
in the net right you can see the website
remember what Internet it is the local
website in your campus so in your school
or in college
there must be intranet where you have
some some local websites for your school
which you can open only in your school
system that is internet that means local
and when I talk about internet it is
global right similarly we have
intermolecular and intramolecular
hydrogen model all right so when you say
in term of liquid hydrogen bond that
means you are talking about two
different molecules right is never in
this case HF again the number HF here we
will get a partial negative charge this
they will get a partial positive charge
and they will be born within the right
water also has same thing h2o
slightly positive slightly positive IIT
negative again will remember water
molecule somewhere here so this will
have slightly negative charge here and
we're talking here was this correct
smelling ah more water molecule that
suppose you have slightly positive
slightly positive slightly negative this
guy was very attracted because the
hydrogen bonds right so it's interim
molecule that means you have two
different molecules and there's a bond
talk about intramolecular hydrogen bond
that means it is local it is within the
same molecule right that means you see
when hydrogen atom is in between 2
electronegative atoms fluorine oxygen ID
is the same only good example if you see
in this case there is a hydrogen here is
oxygen here and there is a bond between
them right this is called in ramallah
this local it's localized within the
same molecule will talk about
intermolecular you talk about two
different models so till now we have
seen to gain a bond covalent bond
hydrogen bond
let's tell you the difference between
hydrogen bond and colvin so that they
should not be in doubt in talk about
hydrogen bond it involves dipole-dipole
interaction will send you more about
this brain talk but Wonderwall force in
the next chapter we talk about covalent
bond was sharing of electrons right
example in this case I have HF there is
a dipole created negative here plus here
the more H shape you have has negative
here it's plus word is a bond between
them
let's call hydrogen bond for covalent
bond is a sharing of electron right
hydrogen bond is formed between hydrogen
atoms and fluorine oxygen and nitrogen
but covalent bond is formed between two
electronegative atoms both of which are
not willing to give electrons will share
the electron hydrogen what is the very
real pond and Cohen what is stronger
than hydrogen so the effects of hydrogen
mod it has some effects that's why we
are reading it by studying this bond the
high bending and boiling point molecules
have high melting and boiling point is
their fraction one example water is
liquid because it has hydrogen one but
s to s HT I see these are all gases
similar structure but this this liquid
why because of the hydrogen bond
hydrogen bonds are soluble covalent
example water they are less volatile
because there's a bond which is holding
them they have higher viscosity and high
surface tension because somebody is
bringing the molecules together because
they all are molecules water molecule it
supposed and this sub whole which is
binding them up right so that's why they
are they are higher viscosity and high
surface tension and if you see the
expansion of water on freezing this can
be explained by hydrogen bomb see in
normal case there are so many water
molecules and they are attracted by
hydrogen bond so they have they are I
mean more dense it by less space but
then we went to freeze it it becomes
eyes this hydrogen bond against weaker
because it takes the crystalline shape
this hydrogen bond becomes weaker so it
expands hope we understand this it is
water the hydrogen bond is strong it
binds the water molecule together and
this is a liquid form it is dense and
occupies less space but the moment you
freeze it the hydrogen bond becomes
weaker it from the crystalline structure
and expands because the hydrogen mode is
we go there thank you
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