# 14.1 Types of reactions  (Page 2/4)

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[link] shows some of the general rules about the solubility of different salts based on a number of investigations:

 Salt Solubility Nitrates All are soluble Potassium, sodium and ammonium salts All are soluble Chlorides, bromides and iodides All are soluble except silver, lead(II) and mercury(II) salts (e.g. silver chloride) Sulphates All are soluble except lead(II) sulphate, barium sulphate and calcium sulphate Carbonates All are insoluble except those of potassium, sodium and ammonium Compounds with fluorine Almost all are soluble except those of magnesium, calcium, strontium (II), barium (II) and lead (II) Perchlorates and acetates All are soluble Chlorates All are soluble except potassium chlorate Metal hydroxides and oxides Most are insoluble

Salts of carbonates, phosphates, oxalates, chromates and sulphides are generally insoluble.

## Testing for common anions in solution

It is also possible to carry out tests to determine which ions are present in a solution. You should try to do each of these tests in class.

As always when working with chemicals, you must work carefully as you can easily get bad chemical burns if you spill the chemicals on yourself.

## Test for a chloride

Prepare a solution of the unknown salt using distilled water and add a small amount of silver nitrate solution. If a white precipitate forms, the salt is either a chloride or a carbonate.

${\mathrm{Cl}}^{-}+{\mathrm{Ag}}^{+}+{\mathrm{NO}}_{3}^{-}\to \mathrm{AgCl}+{\mathrm{NO}}_{3}^{-}$
( $\mathrm{AgCl}$ is white precipitate)
${\mathrm{CO}}_{3}^{2-}+2{\mathrm{Ag}}^{+}+2{\mathrm{NO}}_{3}^{-}\to {\mathrm{Ag}}_{2}{\mathrm{CO}}_{3}+2{\mathrm{NO}}_{3}^{-}$
( ${\mathrm{Ag}}_{2}{\mathrm{CO}}_{3}$ is white precipitate)

The next step is to treat the precipitate with a small amount of concentrated nitric acid . If the precipitate remains unchanged, then the salt is a chloride. If carbon dioxide is formed, and the precipitate disappears, the salt is a carbonate.

$\mathrm{AgCl}+{\mathrm{HNO}}_{3}\to$ (no reaction; precipitate is unchanged)

${\mathrm{Ag}}_{2}{\mathrm{CO}}_{3}+2{\mathrm{HNO}}_{3}\to 2{\mathrm{AgNO}}_{3}+{\mathrm{H}}_{2}\mathrm{O}+{\mathrm{CO}}_{2}$ (precipitate disappears)

## Test for a sulphate

Add a small amount of barium chloride solution to a solution of the test salt. If a white precipitate forms, the salt is either a sulphate or a carbonate.

${\mathrm{SO}}_{4}^{2-}+{\mathrm{Ba}}^{2+}+{\mathrm{Cl}}^{-}\to {\mathrm{BaSO}}_{4}+{\mathrm{Cl}}^{-}$ ( ${\mathrm{BaSO}}_{4}$ is a white precipitate)

${\mathrm{CO}}_{3}^{2-}+{\mathrm{Ba}}^{2+}+{\mathrm{Cl}}^{-}\to {\mathrm{BaCO}}_{3}+{\mathrm{Cl}}^{-}$ ( ${\mathrm{BaCO}}_{3}$ is a white precipitate)

If the precipitate is treated with nitric acid, it is possible to distinguish whether the salt is a sulphate or a carbonate (as in the test for a chloride).

${\mathrm{BaSO}}_{4}+{\mathrm{HNO}}_{3}\to$ (no reaction; precipitate is unchanged)

${\mathrm{BaCO}}_{3}+2{\mathrm{HNO}}_{3}\to \mathrm{Ba}{\left({\mathrm{NO}}_{3}\right)}_{2}+{\mathrm{H}}_{2}\mathrm{O}+{\mathrm{CO}}_{2}$ (precipitate disappears)

## Test for a carbonate

If a sample of the dry salt is treated with a small amount of acid, the production of carbon dioxide is a positive test for a carbonate.

$\mathrm{Acid}+{\mathrm{CO}}_{3}^{2-}\to {\mathrm{CO}}_{2}$

If the gas is passed through limewater and the solution becomes milky, the gas is carbon dioxide.

${\mathrm{Ca\left(OH\right)}}_{2}+{\mathrm{CO}}_{2}\to {\mathrm{CaCO}}_{3}+\mathrm{H}{}_{2}\mathrm{O}$ (It is the insoluble ${\mathrm{CaCO}}_{3}$ precipitate that makes the limewater go milky)

## Test for bromides and iodides

As was the case with the chlorides, the bromides and iodides also form precipitates when they are reacted with silver nitrate. Silver chloride is a white precipitate, but the silver bromide and silver iodide precipitates are both pale yellow. To determine whether the precipitate is a bromide or an iodide, we use chlorine water and carbon tetrachloride ( ${\mathrm{CCl}}_{4}$ ).

anyone know any internet site where one can find nanotechnology papers?
research.net
kanaga
Introduction about quantum dots in nanotechnology
what does nano mean?
nano basically means 10^(-9). nanometer is a unit to measure length.
Bharti
do you think it's worthwhile in the long term to study the effects and possibilities of nanotechnology on viral treatment?
absolutely yes
Daniel
how to know photocatalytic properties of tio2 nanoparticles...what to do now
it is a goid question and i want to know the answer as well
Maciej
Abigail
for teaching engĺish at school how nano technology help us
Anassong
Do somebody tell me a best nano engineering book for beginners?
there is no specific books for beginners but there is book called principle of nanotechnology
NANO
what is fullerene does it is used to make bukky balls
are you nano engineer ?
s.
fullerene is a bucky ball aka Carbon 60 molecule. It was name by the architect Fuller. He design the geodesic dome. it resembles a soccer ball.
Tarell
what is the actual application of fullerenes nowadays?
Damian
That is a great question Damian. best way to answer that question is to Google it. there are hundreds of applications for buck minister fullerenes, from medical to aerospace. you can also find plenty of research papers that will give you great detail on the potential applications of fullerenes.
Tarell
what is the Synthesis, properties,and applications of carbon nano chemistry
Mostly, they use nano carbon for electronics and for materials to be strengthened.
Virgil
is Bucky paper clear?
CYNTHIA
carbon nanotubes has various application in fuel cells membrane, current research on cancer drug,and in electronics MEMS and NEMS etc
NANO
so some one know about replacing silicon atom with phosphorous in semiconductors device?
Yeah, it is a pain to say the least. You basically have to heat the substarte up to around 1000 degrees celcius then pass phosphene gas over top of it, which is explosive and toxic by the way, under very low pressure.
Harper
Do you know which machine is used to that process?
s.
how to fabricate graphene ink ?
for screen printed electrodes ?
SUYASH
What is lattice structure?
of graphene you mean?
Ebrahim
or in general
Ebrahim
in general
s.
Graphene has a hexagonal structure
tahir
On having this app for quite a bit time, Haven't realised there's a chat room in it.
Cied
what is biological synthesis of nanoparticles
what's the easiest and fastest way to the synthesize AgNP?
China
Cied
types of nano material
I start with an easy one. carbon nanotubes woven into a long filament like a string
Porter
many many of nanotubes
Porter
what is the k.e before it land
Yasmin
what is the function of carbon nanotubes?
Cesar
I'm interested in nanotube
Uday
what is nanomaterials​ and their applications of sensors.
how did you get the value of 2000N.What calculations are needed to arrive at it
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The fundamental frequency of a sonometer wire streached by a load of relative density 's'are n¹ and n² when the load is in air and completly immersed in water respectively then the lation n²/na is
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