YouTube Transcript: Chapter 7.2b Acid-Base Reactions and Solubility
Skip watching entire videos - get the full transcript, search for keywords, and copy with one click.
Share:
Video Transcript
Video Summary
Summary
Core Theme
This content defines acid-base reactions as the transfer of a hydrogen ion (H+) between chemical species. It distinguishes between acids (yielding hydronium ions, H3O+) and bases (yielding hydroxide ions, OH-), and introduces neutralization as a specific type of acid-base reaction producing salt and water.
hi class this video is going to be on
acid-base reactions and solubility our
learning goals are to Define what an
acid-base reaction is and then to be
able to identify whether reaction is an
acid-base reaction
we're also going to identify common
acids and bases
so there's going to be some vocabulary
associated with acid-base reactions
first an acid-base reaction is one in
which we have the transfer of a hydrogen
ion this would be h plus it's going to
be transferred from one chemical species
to another so you can think of it as
being transferred from one reactant to
the other reactant and an acid is going
to be a substance that when dissolved in
water yields hydronium ions h3o plus so
we can look at an example here we have
hydrochloric acid as our example which
we'll learn is a strong acid
and the reaction written we have
hydrochloric acid which is dissolved in
water right so it's aqueous when it
reacts with the water molecules right
H2O it actually will donate the proton
in hydrochloric acid to the water
molecule and when it does that water H2O becomes
becomes
h3o plus hydronium ions and so this is
The Telltale
way of us to identify that hydrochloric
acid is an acid and the fact that it
donates its proton
uh to water to generate these hydronium
ions and later we'll learn how we can
gauge the strength of a of an acid by
how much hydronium ions it can generate
so this is an example of an acid-base
reaction because our definition said
that an acid-base reaction is one in
which we have the transfer of h plus
hydrogen ion and that is what we're
seeing here as hydrochloric acid donates
now the previous slide said that
hydrochloric acid is a strong acid and
what that means is that every
hydrochloric acid molecule so every HCL
molecule we have in solution is going to
dissolve and react with water to undergo
this reaction
and this means that we're going to see a
complete reaction of hydrochloric acid
with water in the end there will be no
HCL together right instead we'll have
the chloride ion and the hydronium ions
left in our solution
there are a number of other strong acids
that react this way you can see this
table here lists them we've got
hydrobromic acid hydrochloric acid and
hydroiodic acid so here you can see
these are some of our hydrohalic
acids so acids made from the halogens
we also have nitric acid perchloric acid
and sulfuric acid and you can see the
way that they're written we tend to
write the hydrogen first so you can see
the hydrogen that is going to be donated
in that acid-base reaction
now if there are strong acids acids that
react completely to generate hydronium
ions there are also weak acids and these
weak acids will only partially react to
generate hydronium ions
so for a weak acid when it is dissolved
in water a large majority of the
molecules are going to remain in their
original form meaning that they're not
going to give up their hydrogen ions
they're going to stay as their molecular form
form
so an example here is acetic acid
ch3cooh right so in this case an acetic
acid this hydrogen at the end is the
hydrogen that can be donated as h plus
and this is going to be donated to the
water molecule to generate the hydronium
ions that we know are characteristic of
an acid
now uh in solution the amount of acetic
acid that actually undergoes this
reaction is only about one percent so
you can see that this is really a
limited partial reaction of acetic acid
to make hydronium ions and in contrast
to what we saw in the strong acids which
completely reacted right this is only
reacting a small amount
so we can denote this in our reaction by
writing that our reaction is only
partial by indicating the double-sided
Arrow to show us that we don't
completely go to the right to form our
products but that's some of the
reactants remain in their original form
so is this an acid-base reaction
the answer should be yes because here we
do see the donating of a proton h plus
from one reactant to another and so this
does qualify as an acid-base reaction
there are other examples of weak acids
so we said acetic acid is a common weak
acid so this is the
um the chemical structure for acetic
acid is a component that is found in
vinegar and that's often used for
cleaning and we also know of citric acid
right which is a common weak acid found
in our citrus fruits which you can see
over here on the left and this one has a
number of acidic hydrogens which it can
donate the acidic hydrogen on acetic
so now that we've talked about acids we
can also go and describe what a base is
so a base is a substance that will
dissolve in water to yield hydroxide
ions so acid molecules give us hydronium
ions and bases are going to give us
hydroxide ions so we have an example
reaction written for sodium hydroxide
so when this is dissolved in water it
can dissociate into its ions to give us
sodium ions and the hydroxide ions that
are characteristic of a base
so a lot of our common bases are ionic
compounds composed of our Alkali or
alkaline earth metals right so our group
one and group two metals that are with
hydroxide ions right so sodium hydroxide
which is shown here is one example of
that it would be an Alkali Earth metal
right the sodium which is present with
the hydroxide ions so other examples we
could have potassium hydroxide or
calcium hydroxide or barium hydroxide
right these being some of our group two
alkaline earth metals
so all of these bases are called strong
bases because they are going to
completely dissociate in solution so for
every one mole of strong base that you
dissolve in water you will generate one
mole of hydroxide ions right we'll have
so we say this reaction is complete you
can notice that our arrow is a single
Arrow so that tells us that it's going
to go completely in the right direction
that it is not partial now our question
is this an acid base reaction the answer
and we said that our definition of an
acid-base reaction is one in which we
have the transfer of a proton so here we
do not have any transfer taking place
instead the sodium hydroxide right this
ionic compound is just dissociating into
its constituent ions breaking apart into
the sodium ion and the hydroxide ion so
now if we have strong bases we should
have learned now that we will also have
weak bases some of the compounds that
are weak bases will react with water to
produce our hydroxide ions meaning that
the hydroxide ion isn't present
initially as part of the base but
instead upon reacting with water it will
generate the hydroxide ions
so an example is seen of this ammonia
ammonia is NH3 right we have learned how
to draw ammonia
using our Lewis structures and Vsepr
theory uh thinking about what that
structure looks like
um the nitrogen in ammonia can react
with water to um
to accept a proton from the water and
you can see we go from having NH3 to
having nh4 plus right ammonium
so when that does that we see that the hydrogen
[Music]
when that happens we see that the a
hydrogen from the water is actually
being donated to the ammonia and when
that happens we generate ammonium now
the water having given up one of its
hydrogens will then be left as hydroxide
ions and so this is what classifies
ammonia as a base in this case is this
an acid-base reaction yes right we said
that we see a hydrogen ion being
transferred from the water to the
ammonia to form our ammonium ion and
now lastly we can have something called
a neutralization reaction a
neutralization reaction is a specific
type of acid-base reaction where our
reactants are acid and base right so you
would think of a neutralization reaction
the acid and the base are neutralizing
each other
and the products of this reaction are
always consistently going to be salt and water
water
so here we have an example where we have
magnesium hydroxide so this is our base
which is reacted with hydrochloric acid
right so this is our one of our acids
and so they are reacting together to
neutralize each other and the product of
the reaction is going to be a salt so
here we see that the magnesium chloride
is the salts and then finally water is
our second product
so here we have a neutralization
reaction between an acid and a base and
I should also qualify that a
neutralization reaction we can't have
Click on any text or timestamp to jump to that moment in the video
Share:
Most transcripts ready in under 5 seconds
One-Click Copy125+ LanguagesSearch ContentJump to Timestamps
Paste YouTube URL
Enter any YouTube video link to get the full transcript
Transcript Extraction Form
Most transcripts ready in under 5 seconds
Get Our Chrome Extension
Get transcripts instantly without leaving YouTube. Install our Chrome extension for one-click access to any video's transcript directly on the watch page.
