Hardness of Water | Temporary | Permanent
Summary
TLDRThis video delves into the concept of water hardness, a property influenced by dissolved calcium and magnesium salts. Hard water fails to lather with soap due to these salts, leading to scum formation. The hardness is categorized into temporary, caused by bicarbonates and carbonates removable by boiling, and permanent, from other salts like sulfates and chlorides, requiring treatments like zeolite or ion exchange for removal. The video promises to explore hardness calculations in subsequent lectures.
Takeaways
- 💧 Water hardness is a property that affects how water interacts with soap, preventing it from lathering properly.
- 🔍 Hard water contains dissolved salts of calcium and magnesium, which are responsible for its hardness.
- 🧼 The inability to lather with soap is a key indicator of water hardness due to the reaction between calcium/magnesium ions and soap's fatty acid salts.
- 🌟 There are two main types of water hardness: temporary and permanent, distinguished by the salts present and their reactivity.
- 🕒 Temporary hardness is caused by bicarbonates and carbonates of calcium and magnesium, which can be removed by boiling the water.
- 🔬 Permanent hardness is due to other salts like chlorides, sulfates, nitrates, and phosphates, which do not remove easily by boiling.
- 🧪 A simple test to identify hard water is by adding soap and observing if a white precipitate, or scum, forms, indicating the presence of hardness.
- 🌡 Boiling water can convert bicarbonates to carbonates, which then precipitate out, thus reducing temporary hardness.
- 🛠 To remove permanent hardness, methods like using zeolite, lime soda process, or ion exchange resins are employed.
- ⏩ The lecture will continue with calculations related to water hardness in the next session.
Q & A
What is water hardness?
-Water hardness is a property of water that prevents it from lathering with soap properly due to the presence of dissolved salts of calcium and magnesium.
Why does hard water not lather with soap?
-Hard water contains calcium and magnesium salts that react with the sodium or potassium salts of higher fatty acids in soap, leading to the formation of a precipitate or scum, which prevents proper lathering.
What are the two main types of water hardness?
-The two main types of water hardness are temporary hardness and permanent hardness.
What causes temporary hardness in water?
-Temporary hardness is caused by the presence of bicarbonates and carbonates of calcium and magnesium in the water, which can be removed by boiling.
How can you remove temporary hardness from water?
-Temporary hardness can be removed by boiling the water, which causes the bicarbonates and carbonates to convert into precipitates that can be filtered out.
What is permanent hardness and how is it different from temporary hardness?
-Permanent hardness is caused by salts other than bicarbonates and carbonates, such as chlorides, sulfates, nitrates, and phosphates of calcium and magnesium, and cannot be removed by boiling alone.
What are some methods to remove permanent hardness from water?
-Permanent hardness can be removed using methods like ion exchange, zeolite, or lime soda processes, which involve the use of compounds like zeolite, calcium hydroxide, or sodium carbonate.
Why is it important to identify water hardness?
-Identifying water hardness is important to determine the suitability of water for various applications, such as domestic use, agriculture, and industrial processes, where hard water can cause scaling and other issues.
What is pseudo hardness and how does it differ from temporary and permanent hardness?
-Pseudo hardness, also known as fake hardness, is not discussed in detail in the script but generally refers to hardness caused by certain metals other than calcium and magnesium, which can be removed by simple settling or filtration.
How can you differentiate between hard and soft water?
-Hard water can be identified by its inability to lather with soap and the presence of a white precipitate or scum, while soft water will lather easily and not produce a precipitate.
What are the potential issues caused by hard water in domestic use?
-Hard water can cause issues such as scaling in pipes and appliances, reduced efficiency of water heaters, and difficulty in cleaning with soap, which can affect the quality of laundry and dishes.
Outlines
💧 Understanding Water Hardness
The first paragraph introduces the concept of water hardness, explaining it as a property of water that prevents it from lathering with soap effectively. It is caused by the presence of dissolved salts of calcium and magnesium. The speaker discusses the reaction between these salts and soap, which typically results in a precipitate or scum, indicating hard water. The paragraph also distinguishes between two types of hardness: temporary and permanent, with a brief mention of pseudo hardness. The focus is on how the presence of calcium and magnesium salts in water leads to hardness and the inability to lather with soap.
🔍 Temporary vs. Permanent Hardness
The second paragraph delves deeper into the two types of water hardness: temporary and permanent. Temporary hardness is caused by bicarbonates and carbonates of calcium and magnesium, which can be removed by boiling the water. This process converts the bicarbonates into carbonates, leading to the formation of precipitates that can be filtered out. Permanent hardness, on the other hand, is due to other salts such as chlorides, sulfates, nitrates, and phosphates, which do not convert into precipitates upon boiling. The paragraph also introduces the terms 'carbonate hardness' for temporary and 'non-carbonate hardness' for permanent, highlighting the difference in the ions responsible for each type.
🛠 Methods to Remove Hardness
The third paragraph discusses methods to remove water hardness. For temporary hardness, boiling is an effective method as it converts bicarbonates into insoluble carbonates, which can then be filtered out. For permanent hardness, more complex treatments are required, such as the use of zeolite, lime soda process (involving calcium hydroxide and sodium carbonate), or ion exchange resins. The paragraph concludes by summarizing the discussion on water hardness and its types, with a预告 of the next lecture focusing on the calculation of hardness.
Mindmap
Keywords
💡Hardness of Water
💡Dissolved Salts
💡Soap
💡Precipitate
💡Temporary Hardness
💡Permanent Hardness
💡Bicarbonates and Carbonates
💡Zeolite
💡Lime Soda Process
💡Ion Exchange Resin
Highlights
Definition of water hardness as a property that prevents soap from lathering properly.
Presence of dissolved salts of calcium and magnesium causes water hardness.
Hard water's interaction with soap leads to a white precipitate known as scum.
Differentiation between dissolved, suspended, and biological impurities in water.
Soap is identified as the sodium or potassium salt of higher fatty acids.
Chemical reaction between hard water minerals and soap results in scum formation.
Explanation of temporary hardness due to bicarbonates and carbonates of calcium and magnesium.
Temporary hardness can be removed by boiling water, which converts bicarbonates to carbonates.
Permanent hardness is caused by salts other than bicarbonates and carbonates, such as sulfates and chlorides.
Permanent hardness is more difficult to remove and requires processes like zeolite, lime soda, or ion exchange.
Temporary hardness is also referred to as carbonate hardness, while permanent hardness is known as non-carbonate hardness.
The practical test for water hardness involves adding soap and observing the formation of scum.
The video differentiates between alkaline hardness (temporary) and non-alkaline hardness (permanent).
The importance of identifying water hardness for its application in various processes.
The video concludes with a preview of the next lecture focusing on the calculation of water hardness.
Transcripts
hello everyone
so uh today i will discuss about a
property of water
which is known as hardness of water
in the previous video i discussed about
what are the basic sources of water
and what are the impurities which could
be possibly present in the water
based on that if those impurities are
present
they may render a property called
hardness to the water
so what is that it's basically a
property of water
by virtue of which it does not give
leather with soap
properly so if the water
contains certain salts
due to the presence of dissolved salts
of calcium and magnesium
there are two three things in this
definition first of all
the salts are dissolved in nature i hope
you remember
that the impurities could be dissolved
could be suspended
and could be biological so in the
category of dissolved salts
especially of calcium and magnesium if
these salts are present in the water
the water is known as hard water so
if a hard water is taken and as per the
definition
it do contains calcium and magnesium
salts
dissolved in it now if you treat this
kind of water
with soap this particular water
is not going to give you leather with
soap properly
and this property is known as hardness
of water
if the property because of which water
does not
leather with soap properly now why does
it does not leather with soap
because certain salts like that
of calcium and magnesium say for example
calcium chloride
is present in the water now if you take
this water with soap
i hope you remember that the soap was
sodium
or potassium salt of higher fatty acid
so it could be n a it could be k sodium
or potassium salt of higher
fatty acid rco h
fatty acid and then in this r since i'm
saying it's higher fatty acid
this r uh could be cn h2n
plus one so let's say if i take steric
acid
it could be c 17 h 35 that is
r then c o o n a
so this becomes sodium stearate so if we
have taken this kind of compound
this is a so right if you take oleic
acid
it will become oleate if you take
palmitic acid it will become palmitate
so basically soap is sodium or potassium
salt of
higher fatty acid now imagine you are
having a hard water which is having
calcium or magnesium salt
and you treat it with soap so what do
you think the reaction would be
obviously these are going to react so
this is the positive ion here
this is the positive ion here so at the
end
uh you will be having a displacement
reaction
so herein if i write it like this
and then like this so overall if i want
to
you know balance out the reaction i
could uh write to
yeah so this is a precipitate and you
call it as a scar
this is the down arrow which shows it's
a precipitate so
if the water is hard if it is having
presence of calcium magnesium ions
which are dissolved in nature so you
cannot see them
but they are present in the water what
do they do they render hardness to the
water
so if that water you take and you treat
it with soap
you'll be immediately able to identify
because of the white precipitate
which you call it as a scum you'll be
able to identify
that the water is hard so basically
hot water and soft water is the first
key you need to find out whether the
water is hard or not
then only you can utilize it in your
further application
so if it is hard that means it's not
going to give leather with soap properly
and that too due to the presence of
dissolved salts of
calcium and a magnesium so i hope
if i simply now write another salt
like if i take magnesium sulfate i think
you'll be able to react it with this and
you'll be able to understand
that here you will get magnesium
stearate
and you can change the anion here also
so i think you are able to understand
the fact
now there are two basic types of
hardnesses
temporary and permanent there is one
more
which is known as uh pseudo hardness
that is a fake hardness i'll tell you
later on about this
but as of now we are going to discuss
about temporary and permanent hardness
let's go ahead with it temporary
hardness
what do you think it is the word itself
suggests
that it is temporary in nature that
means
it is a hardness hardness means first
point
is not going to give leather with soap
properly
don't forget second point why dissolved
salts of calcium
and magnesiums are present now if
these salts some of the salts they may
render the hardness in temporary nature
means for a short period of time and
some of the salts may remain present in
the water
for long so temporary hardness is
nothing but
the hardness due to which there will be
no leather definitely
but here the salt which are present
are of calcium magnesium definitely what
is the difference
the difference lies in which salt i'm
talking about
bicarbonates and carbonates so only
and only if bicarbonates
and carbonates of calcium and magnesium
are present
you can call that hardness is temporary
in nature
because it does not last long you can
easily remove it how can you remove it
by boiling the water so these are the
example
and in fact magnesium carbonate will
also
come here so basically these four salts
are responsible
for rendering hardness to the water and
that too
temporary in nature temporary you can
remove them
easily now coming to the next one
obviously per month so in comparison to
that temporary
which was easily removed by boiling
obviously this type of hardness
you cannot easily remove by boiling that
prevents the leather quite permanently
and here also
you need to specify which salts
are responsible for it so if i can
say conveniently except by carbonate and
carbonate
all salts are responsible for permanent
hardness
chlorite sulfates nitrates phosphates
etc
right so it would be very easy for you
to understand by the formula
itself like if i write magnesium sulfate
as of now
you can see that it is not bicarbonate
and carbonate
that means it's permanent in nature
right
if i write magnesium carbonate what
would it be
it's a carbonate so temporary let's say
if i write calcium carbonate
what it is temperature like
if i write calcium chloride that's not a
carbonate bicarbonate
so obviously permanent let's say calcium
bicarbonate
what it would be obviously temporary so
with the help of
the formula itself you should be able to
understand
that if it is bicarbonate and carbonate
it is temporary and rest all salts rest
all
comes in the category of permanent so
just to revise the fact
one more time temporary hardness is
quite
temporary in nature as simple as that
that's quite permanent in nature but the
difference
lies in the reason behind it here the
reason is bicarbonates and carbonates
here all salts except bicarbonate and
carbonate
you can write one example in both of the
categories
now it is also known as alkaline
hardness
and it is also known as non-alkaline
hardness can you identify
why i think it will focus
on the ions which are responsible
bicarbonates and carbonates
right the ions or
maybe hydroxide uh then
you can say that these are alkaline
image while these ions are not alkaline
they're quite acidic you can see there
right so you can call them as non alkali
at the same time carbonate hardness
i guess you remember it was because of
bicarbonate and carbonate
so the another name of temporary
hardness would be carbonate hardness
another name of permanent hardness would
be non-carbonate heartless
the important point here is you can
remove it by boiling
so what happens is if you boil let's say
if you have
magnesium bicarbonate and if you heat it
it changes to magnesium hydroxide
fine and then you can balance out the
reaction by writing it co2 and on
so basically magnesium gets converted to
magnesium hydroxide
calcium gets converted to calcium
carbonate so when you boil the water
this is the sign triangle is the sign of
heating so when you're heating the water
when you're boiling the water
these ions gets converted into their
respective
precipitate and then you can simply
filter them up
so by filtering by simply removing uh
you can remove them
right so by simple boiling they are
going to convert their
into their respective stable form and
that is how
they render the hardness in a temporary
manner
because they easily get converted into
their stable form
when these of the ions are quite stable
and they don't undergo this reaction
very easily
right for them you have to use certain
compounds
like you can use zeolite or permuted you
can use lime soda
lime uh would be calcium hydroxide
soda would be sodium carbonate then you
can use iron exchange resin
etc so these points are to be like
processes are to be used
in order to remove the permanent
hardness so i think
with that i'm able to give you a glimpse
on
what is uh what do you understand by the
term hardness
and then and its types so today uh what
we have discussed
is only hardness and its types in the
next lecture
i would focus more on calculation of
hardness
uh that's all for today so thank you
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