‫‪CHEMISTRY-101‬‬
‫إعداد العلوم الطبيعية‬
‫العمــــــــــــــــلي‬
‫أ‪.‬د‪ .‬أحمد خميس سالمة‬
‫د‪ .‬شلبي عبد الغفار يس‬
‫د‪ .‬عمران عبد الاله عمران‬
1. Safety Rules, First aid and Glassware in
Chemical Laboratories
Safety rules in the chemical laboratory:

You have to come in time without delay.

White coat used to protect your clothes from any deterioration.

You have to study and understand the experiment very well.

Do not touch, smell, or taste any material or chemical

Use the pipette filler to take any portion of liquid chemical, do not suck
with your mouth.

Do not inhale the vapors of chemicals or solvents.

Do not waste in consuming chemicals.

Do not eat or drink inside the lab.

Put the flammable solvents away from fire.

Be careful during heating or boiling any chemical in a test tube

All chemical reactions and processes which release vapors or gases
should be carried out inside the hood.

To dilute the concentrated acids, it should be added to the water
gradually and carefully with stirring. Do not add water to the acid.

The distillation processes for flammable solvents should be done in
closed system using electrical bath water. Do not use direct flame.
The sources of danger inside the laboratory:
1. Toxic chemicals.
2. Flammable chemicals.
3. Explosive chemicals.
4. Glassware.
2
First aid in the chemical laboratory:
Acid burning:

Wash the burnt area with a gentle stream of water.

Wash the burnt area with 5% of sodium hydrogen carbonate solution.

Wash with water again.
Alkali burning:

Wash the burnt area with a gentle stream of water.

Wash the burnt area with 5% of ammonium chloride solution.

Wash with water again.
Phenol or bromine irritating:

Wash the irritated area with organic solvent , e.g., alcohol, ether, or
benzene.
Flame burning:

Wash the burnt area with 5% potassium permanganate.

In case of slightly burning, wash with alcohol and put layer of glycerin.
Eye hurtful:

If alkali material reach the eye, wash eye with a lot of water and then
wash with 2% boric acid solution.

If acid material reach the eye, wash eye with saturated solution of
borax or 5% of sodium hydrogen carbonate solution.

You have to go to hospital if any accident happened to eye.
Precautions to avoid harmful during the handling of glassware:

Take care during inserting thermometer or glass tube into hole of
rubber plug. You can wet the tip of tube with glycerol or water.

Use silicone grease to connect two or more pieces of glass.
Chemical label:

Read the label of chemicals carefully.

Take only the amount you need in a beaker or test tube.
3

Do not deteriorate the chemicals by returning the remained amount
to the bottle.


Cap the bottle directly after taking the amount you need.
There are important special symbols you have to be aware during
the handling of different chemicals:
4
Glassware in Laboratories
Glassware used in lab is resist to chemicals, easy to follow up the
reaction and easy to clean.
Glassware divided into two categories:
[A] Glassware used in heating:
This type of glassware is tolerant for heating even with direct flam
but can not used in measuring.
Examples:
1. Test tubes
5
2. Beakers
They are used in a solution preparation, liquid heating and
precipitation processes.
3. Conical Flasks
Conical flasks are used in titration, heating, and filtration
processes.
4. Round bottom flasks
They are used in preparation of chemical reactions, extraction
and distillation processes.
6
[B] Glassware used in Measuring:
This type is used only in measuring process but does not tolerant
for heating processes.
Examples:
1. Burette: It is used in volumetric titration.
7
2. Pipette: It is used to take a certain volume of liquids.
3. Graduated cylinder: It is used to take a roughly volume of
liquids.
8
4. Volumetric flask: It is used for preparation of concentrations of
solutions
9
Shapes of some tools and glasses used in chemistry lab
Indicator bottle
crucible
Filtering flask
condenser
Separatory funnel
Bunsen burner
Büchner funnel
Mortar
Wash bottle
10
Evaporating Dish
Reagent bottle
Clamp stand,
support
funnel
Desicator
Balance
11
Calibration of measuring glassware
Measuring glass wares such as cylinder, pipette and burette are
different in their precision.
Using mass and density we can calibrate each tool and compare
the volumes.
d
m
(g / mL)
V
If you fill any relatively narrow tube with liquid, the surface of
most liquids has not seen flat but it will be concaved. So, we have
to read the volume at the lower point of that surface as clear in
the following shape:
‫خطأ‬
‫صح‬
‫خطأ‬
Graduated cylinder:
1. Put an empty beaker on balance and record it weight (m1).
2. Using 100 ml cylinder, take 10 ml of water and transfer them
into the beaker. V1= 10 ml.
3. Weigh the beaker + 10 ml water and record the weight (m2).
4. Calculate the mass of 10 ml of water m = m2 –m1.
12
5. Knowing the density of water (1.0063 g/ml) and the mass of
10 ml water, calculate the volume of water V2.
6. Calculate the difference between V1 and V2.
7.
V  (V1  V2 )mL
8. Calculate the error % using the formula:
E% 
V
 100
V1
Graduated burette:
1. Put an empty beaker on balance and record it weight (m1).
2. Using 50 ml burette, take 10 ml of water and transfer them
into the beaker. V1= 10 ml.
3. Weigh the beaker + 10 ml water and record the weight (m2).
4. Calculate the mass of 10 ml of water m = m2 –m1.
5. As described above, calculate the difference between V1 and
V 2.
V  (V1  V2 )mL
6. Calculate the error % using the formula:
E% 
V
 100
V1
13
Graduated pipette:
1. Put an empty beaker on balance and record it weight (m1).
2. Using 10 ml pipette, take 10 ml of water and transfer them
into the beaker. V1= 10 ml.
3. Weigh the beaker + 10 ml water and record the weight (m2).
4. Calculate the mass of 10 ml of water m = m2 –m1.
5. As described above, calculate the difference between V1 and
V 2.
V  (V1  V2 )mL
6. Calculate the error % using the formula:
E% 
V
 100
V1
14
Quantitative analysis
Volumetric Titration
In this process we use standard solutions to measure the strength
of unknown solutions in the presence of indicators.
Reaction categories in volumetric titration:
1. Neutralization reactions: includes reactions between
acids and bases or acid salt with base or basic salt with acid.
2. Precipitation reactions: includes reactions that produce
ion precipitate as insoluble salt.
3. Oxidation reduction reactions: includes reactions that
oxidation number of atoms and ions changed.
generally, chemical reactions are divided into two categories:
1. Reactions happened without electron transfer between
atoms or ions, thus the oxidation number does not change.
For example:
NaOH  HCl
NaCl  H2O
15
2. Reactions happened with electron transfer between atoms or
ions, thus the oxidation number does change. These
reactions named as oxidation reduction reactions.
For example:
Cu2   Zn
Cu  Zn2 
(ÇÎ Ê ÒÇá) Úãáí ÉÅÑÌ ÇÚ
Cu
+2
ÚÇãá ãÄßÓ Ï
ÚÇãá ãÑÌ Ú
+
Zn
Cu
ÚÇãá ãÄßÓ Ï
+
Zn+2
(ãÎ Ê Òá) ÚÇãá ãÑÌ Ú
Úãáí ÉÃßÓ ÏÉ
To get precise results in volumetric titrations you have to:
 Use clean glassware.
 Take homogenous samples.
 Use suitable standard solutions.
 Use indicator to justify the end point of reaction.
Concentrations:
Molarity:
Molarity  M (mol/L) 
Amount of Solute (mole)
Volume of Solution(Liter)
Gram/liter:
C (g/L)
Massof Solute (g)
Volume of Solution(Liter)
16
Mass percent:
%W 
Massof Solute (g)
 100
Massof Mixture (g)
Volume percent:
%V 
Mole fraction:
X
Volume of Solute(mL)
 100
Volume of Mixture (mL)
Amount of Solute(mole)
Amount of Mixture (mole)
pH concept:
pH is the negative logarithm of hydrogen ion concentration
pH = - log [H+]
where:
[H+] is hydrogen ion concentration in a solution.
Thus pH value
changes according the change in H+ and OH- ions. pH range is 0 --- 14
acid + base
salt + water
HCl + NaOH
NaCl + H2O
H  OH 
H2O
If pH value less than 7 , the solution will be acid.
If pH value more than 7 , the solution will be base.
If pH value equal 7 , the solution will be neutral.
Standard materials which used for making standard solutions
should be :
17
 Have high molecular weight.
 Very pure.
 Chemically stable and do not effect by moisture, heat or any
other conditions.
 React very fast and completely with the unknown materials.
18
Determination of NaOH concentration
To determine the concentration of NaOH , we can use known
concentration of the standard acid, potassium hydrogen phthalate
(KHP) in the presence of phenolphthalene indicator (phph).
The indicators show the end point of the reaction because they
have different color in the different pH media.
Indicator
PhPh
MO
Acid media
Base media
Neutral media
Colorless
violet
Slight rose
Red
yellow
Orange
KHP has all advantages of standard materials, high molecular
weight, chemically stable, high purity and does not effect with
moisture.
COOH
.
COOK
Potassium hydrogen phthalate (KHP)
Procedure:
1. Weigh 0.20 g of KHP and dissolve them in 25 ml of distilled
water in a conical flask.
2. Add 2-3 drops of phph indicator to the conical flask contents
(colorless solution).
19
3. Add slowly NaOH to the flask contents through burette.
4. Stop the addition if you reach the slight rose color and
record the consumed volume of NaOH
5. Calculate the concentration of NaOH using the formula:
Vml X CM NaOH = Vml X CM KHP
Calculations:
Equation of the reaction:
Vml NaOH =
Weight of KHP =
0.20 g
Molar mass of KHP=
204.2 g.mole-1
Moles of NaOH =
Moles of KHP =
Molarity of NaOH=
20
Determination of ACIDIC MATERIAL
HYDROCHLORIC ACID
To determine the concentration of HCl acid , we can use known
concentration of NaOH base in the presence of phenolphthalene
indicator (phph) or methyl orange indicator (MO).
HCl + NaOH
NaCl + H2O
Procedure:
1. Take 10 ml of the unknown sample of HCl using pipette and
transfer them to a conical flask.
2. Add 2-3 drops of phph indicator to the conical flask contents
(colorless solution).
3. Add slowly NaOH (0.1 M) to the flask contents through
burette.
4. Stop the addition if you reach the slight rose color and
record the consumed volume of NaOH
5. Calculate HCl concentration using the formula:
Vml X CM NaOH = Vml X CM HCl
21
Calculations:
Equation of the reaction:
Vml HCl =
Vml NaOH =
Molarity of NaOH=
Molarity of HCl=
Moles of NaOH =
Moles of HCl =
22
Determination of copper sulfate
CuSO4
The idea of this determination depends on oxidation reduction
reaction between copper sulfate and excess of zinc metal. We get
ride of the excess of zinc using concentrated HCl.
CuSO4 + Zn
Zn SO4 + Cu
2 HCl + Zn
Zn Cl2 + H2
Procedure:
1. Take 20 ml of the unknown copper sulfate and put them in a
beaker and weigh them.
2. Add excess amount of zinc metal (1 g) in the previous
solution and shake for a period until the blue color
disappeared. The excess amount of zinc to be sure that all
copper in the copper sulfate solution is precipitated.
3. Add 15 ml of concentrated HCl (6M) to the solution and
shack to get ride of the excess of zinc metal. Notice H2 gas.
4. Weigh a filter paper and filter the mixture through it to
collect the all precipitated copper.
5. Wash the copper ppt using water and acetone.
23
6. Dry the ppt. using oven at 100 °C.
7. weigh the filter paper and its contents of copper and record
the weight of Cu.
8. Calculate the density of CuSO4 using the formula
dCuSO4 
m
(g / mL)
V
9. Calculate the molarity of CuSO4 knowing that atomic weight
of Cu is 63.5 g, S is 32, O is 16
10. Calculate the weight % of copper in copper sulfate using
the formula:
%WCu 
mCu
 100
m
Calculations:
Weight of copper sulfate m (g)
Volume of copper sulfate,
V  20mL
Weight of empty filter paper m1(g)
Weight of filter paper + cu ppt
m2 (g)
Weight of the precipitated copper
mCu  m2  m1(g)
The density of copper sulfate
m
dCuSO4  (g / mL)
V
Concentration of copper sulfate
Mmol / L
24
Weight % of copper
m
sulfate %WCu  Cu  100
m
Formula of CuSO4 +
Zn
Formula of HCl +
Zn
25
Qualitative analysis
Inorganic compounds may be found in a liquid or in a solid state.
If the material was found as liquid or in a solution, we have to
follow many steps as:
 Notice the color, smell and other physical properties.

Check the acidity
and alkalinity using litmus paper or any
other indicators to be sure if the compound is neutral, acidic
salt, or basic salt.

Evaporate small amount of the liquid to dryness. If any solid
residues remained,
the material
may
be salt
o
alkali
hydroxides and earth elements which give brown PPt with
AgNO3, blue PPt with CuSO4 or brown reddish PPt with FeCl3.

Acid radical (anions) or basic radical (cations) of the
compound or both of them should be tested.
If the material was found as solid, we have to dissolve the solid
material in an appropriate solvent to be salt solution.
Solubility tests:
Try to dissolve the solid material in the following solvents at the
order of:
 Water,

HCl dil ,

HCl
conc
Hot water
HCl dil + heating
, HCl
conc
+ heating
26

HNO3
dil
, HNO3

HNO3
conc

Aqua regia (3ml of HCl conc + 1ml of HNO3 conc)
dil
, HNO3
+ heating
conc
+ heatin
Note: The solution of any concentrated acid should be diluted with
water before any test.
Equilibrium-constant
Equilibrium-constant expressions are algebraic equations that
relate the concentrations of reactants and products in a chemical
reaction to one another by means of a numerical quantity called
an equilibrium constant.
Consider the generalized equation for a chemical equilibrium
mM + nN
pP + qQ
where the capital letters represent the formulas of participating
chemical species and the italic letters are the small integers
required to balance the equation. Thus, the equation states that m
moles of M react with n moles of N to form p moles of P and q
moles of Q. The equilibrium-constant expression for this reaction
is
K =
[P]p [Q]q
------------[M]m [N]n
Where the letters in brackets represents the molar concentration
of dissolved solutes.
27
Basic radicals (Cations)
Basic radicals are divided into six groups on the basis of solubility
product. Each group precipitated with certain reagent named as
the group reagent.
Electrolytes are solutes which ionize in a solvent to produce an
electrically conducting medium.
Strong electrolytes ionize completely whereas weak electrolytes
are only partially ionized in the solvent.
The group reagent is an electrolyte which gives negative ion
(anion). The concentration of this anion should be enough to reach
the solubility product of its derivatives from certain metals.
Each salt has a certain solubility product at certain tempereature.
When an aqueous solution is saturated with a sparingly soluble
salt, one or more equilibria will be established.
With silver
chloride, for example,
AgCl(s)
AgCl(aq)
AgCl(aq)
Ag+ + Cl-
The solubility product constant (Ksp) of AgCl(aq) = [Ag+] [Cl- ]
[Ag+] [Cl- ] in solution > Ksp of AgCl , the salt will precipitated.
28
So if the product
[Ag+] [Cl- ] less than Ksp of AgCl, we can add
excess of silver or chloride ions to the solution to increase the
product [Ag+] [Cl- ] over Ksp
29
30
First group
Silver (Ag+), Lead (Pb+2), Mercury (Hg2+2)
Simple salt test of silver
AgNO3
Silver, the white metal, is soluble in concentrated nitric acid. Its
symbol is derived from the Latin name Argentum (Ag).
1.
AgNO3 + HCl
AgCl
2.
+
white PPt
AgNO3 + KI
AgI
Yellow PPt
white PPt
Yellow PPt
Amino silver chloride
+
KNO3
is insoluble in ammonia solution
AgNO3 + KCN
AgCN
white PPt
+
KNO3
is soluble in excess of KCN solution
AgCN + KCN
AgNO3 + K2CrO4
Ag2CrO4
HNO3
is soluble in excess of ammonia solution
[Ag(NH3)2]Cl
AgCN
4.
AgCl
AgCl + 2NH3
AgI
3.
white PPt
dil
dark red PPt
K[Ag(CN) 2]
Ag2CrO4
Argento pot. cyanide
dark red PPt
+
2KNO3
is soluble in HNO3 and ammonia solution
31
5. 2AgNO3 + 2NaOH
Ag2O
Brown PPt
Black PPt
Brown PPt
+ 2NaNO3 + H2O
is soluble in HNO3 and ammonia solution
6. 2AgNO3 + H2S
Ag2S
Ag2O
Ag2S
Black PPt
+ 2HNO3 + H2O
is soluble in hot HNO3 dil
32
Simple salt test of Lead
Pb(NO3)2
Lead symbol is derived from the Latin name Plumbum (Pb).
1.
Pb(NO3)2 + HCldil
PbCl2
PbCl2
white PPt
+
HNO3
is soluble in hot water and return again after
white PPt
cooling.
2.
Pb(NO3)2 + 2KI
PbI2
3.
PbCrO4
HNO3
4.
+ K2CrO4
+
2KNO3
PbCrO4
+
Yellow PPt
2KNO3
is insoluble in acetic acid but soluble in
Yellow PPt
and NaOH solution
Pb(NO3)2
PbSO4
Yellow PPt
is slightly soluble in hot water.
Yellow PPt
Pb(NO3)2
PbI 2
+ H2SO4 dil
White PPt
PbSO4
White PPt
+ HNO3
is soluble in ammonium acetate and NaOH
solution
5.
Pb(NO3)2
PbS
Black PPt
+ H 2S
PbS
Black PPt
+ HNO3
is soluble in hot HNO3 dil
33
6.
Pb(NO3)2
+ NaOH
Pb(OH)2
White PPt
Pb(OH)2
White PPt
Pb(OH)2 White PPt
+ NaNO3
is soluble in excess of NaOH
+ 2NaOH
Na2PbO2 + 2 H2O
34
Simple salt test of Hg2++
Hg2(NO3)2
Mercury is a bright liquid metal and its symbol is taken from the
Latin name, Hydrarygrum. Its vapor is toxic
1.
Hg2(NO3)2 + HCldil
Hg2Cl2
white PPt
+
HNO3
Hg2Cl2
white PPt
is soluble in aqua regia (HClconc : HNO3 conc , 3:1).
Hg2Cl2
white PPt
changed to black PPt by adding ammonia solution.
Hg2Cl2
white PPt
+ 2NH3
Hg black + NH4Cl +
Hg(NH2)Clwhite PPt of amino mercuric chloride
2.
Hg2(NO3)2 + 2KI
Hg2I2
green yellowish PPt
Hg2(NO3)2 + 2KI
3.
Hg2(NO3)2 + H2S
4. Hg2(NO3)2 + K2CrO4
Hg2CrO4
Brown PPt
Hg2I2
green yellowish PPt
+ 2KNO3
is soluble in excess of KI
K2(HgI4)
mercuric pot. iodide
+ Hg
HgSblack PPt + HgBlack + 2HNO3
Hg2CrO4 Brown PPt + 2KNO3
changed into red crystalline PPt by boiling.
35
5.
Hg2(NO3)2 + 4NaOH
HgO + Hg2OBlack PPt +Hg +
4NaNO3 + 2H2O
6.
2Hg2(NO3)2 + 4NH3 +H2O
3NH4NO3
+ 2Hg +
HgO.Hg(NH2) NO3 Black PPt of Alkali amino mercuric nitrate
7. 2Hg2(NO3)2 + SnCl2
Hg2Cl2 white PPt + SnCl2 excess
Hg2Cl2 white PPt + Sn(NO3)2
2Hgblack PPt + SnCl4
36
Results
Reagent
HCldil
Ag+
Pb++
Hg2++
White PPt of AgCl
which is soluble in
ammonia
Yellow PPt of PbI2
KI
which is soluble in
hot water.
KCN
K2CrO4
NaOH
H 2S
NH4OH
H2SO4 dil
SnCl2
------
------
White PPt of Hg2Cl2
which converted
into black with
excess of SnCl2
37
Mixture of the first group
The group will be precipitated according to the solubility product.
Chlorides of the first group have the lowest solubility product
comparing with the second, third,….or six group. So, the first
group will be precipitated as chlorides while the chlorides of other
groups will be soluble.
The group reagent of the first group is diluted HCl.
The precipitated ion of the first group is chloride ion.
Small amount of mixture in test tube + HCldil
Put all mixture in a beaker + excess amount of HCl
white PPt
dil
and filter
the mixture and collect the PPt
38
PPt (PbCl2 , AgCl, or Hg2Cl2)
Add hot water
Filtrate 1
May be contains PbCl2
Precipitate 1
May be contains AgCl or Hg2Cl2 or both
Add excess of NH4OH and filter
Filtrate 1
May contains Ag
Precipitate 2
Black PPt, Hg
Add HNO3, if White PPt, there is Ag
Concerning Filtrate 1,
1. Small portion cooled under water stream, if white PPt, it is Pb
2. small portion + H2SO4 dil , if white PPt, it is Pb
3. small portion + potassium chromate , if Yellow PPt, it is Pb
39
Second group
Copper (Cu++), Cadmium (Cd++), Bismuth (Bi+3), Mercury (Hg+2)
Antimony (Sb+3), Arsenic (As+3 , As+5), Tin (Sn+2, Sn+4)
The second group is divided into two sub groups, G II-A
and group II-B according the solubility of their sulfides in
yellow ammonium sulfide where GII-A insoluble while GIIB is soluble.
Group II-A includes Copper (Cu++), Cadmium (Cd++), Bismuth
(Bi+3) and Mercury (Hg+2).
Group II-B includes Antimony (Sb+3), Arsenic (As+3 , As+5) and
Tin (Sn+2, Sn+4)
40
Simple salt test of Hg2++
HgCl 2
1.
3HgCl 2 + 2H2S
Hg3Cl2S2
Hg3Cl2S2 + H2Sexcess
2.
HgCl2 + 2KI
HgI2
red PPt
HgI2 + 2KI
white PPt
+
2HCl + 3HgS
HgI2
red PPt
HNO3
black PPt
+ 2KCl
is soluble in excess of KI
excess
3. HgCl2 + NH4OH
K2(HgI4)
mercuric pot. iodide
HgNH2Cl + HCl + H2O
White PPt of amino mercuric chloride
4. HgCl2 + NaOH
NaCl + HgOHCl
red PPt
41
Simple salt test of Cu++
CuSO4
Copper is a red metal and its symbol is taken from the Latin name
Cuprum.
1.
CuSO4 + H2S
2. 2CuSO4 + 2NH4OH
H2SO4 +
CuS Black ppt
CuSO4.Cu(OH)2
CuSO4.Cu(OH)2 + 4NH4OHexcess
green PPt
+ (NH4)2SO4
2Cu(NH3)4SO4
+ 8H2O
Deep blue color
of amino copper sulfate
3. CuSO4 + 2NaOH
Cu(OH)2
4.
Blue greenish PPt
CuSO4 + 2KI
2CuI2
white PPt
5. CuSO4 + 2KCN
Cu(CN)2 + 2KCN excess
Cu(OH)2
Δ
Blue greenish PPt
CuO Black ppt
CuI2
Cu2I2
white PPt
+
+ Na2SO4
H 2O
+ K2SO4
+ I2 Brown color
Cu(CN)2
Brown yellowish PPt
+ K2SO4
K2[Cu(CN)4]
Copprous pot. Cyanide
42
6. CuSO4 + 2KSCN
Cu(SCN)2
Black PPt
Cu(SCN)2
Black PPt
+ K2SO4
is soluble in excess of KSCN giving a green color
7. 2CuSO4 + K4[Fe(CN)6]
Cu2[Fe(CN)6] + K2SO4
Brown PPt of
coppric ferro cyanide
Cu2[Fe(CN)6] is soluble in ammonia giving a deep yellow color
43
Simple salt test of Cd++
CdCl2
1.
CdCl2 + H2S
2.
CdCl2 + 2NH4OH
Cd(OH)2
white PPt
CdS Yellow ppt
Cd(OH)2
+ 2 HCl
+ 2NH4Cl
white PPt
+ NH4OH excess
[Cd(NH3)4] (OH)2
amino cadmium hydroxide
3. CdCl2 + 2NaOH
4. CdCl2 + 2KCN
Cd(CN)2 + 2KCN excess
Cd(OH) 2
Cd(CN)2
white PPt
white PPt
+ 2NaCl
+ 2KCl
K2[Cd(CN)4]
Cadmium pot. Cyanide
5. 2 CdCl2 + K4[Fe(CN)6]
Cd2[Fe(CN)6] + 4 KCl
White PPt of
cadmium ferro cyanide
44
Simple salt test of Bi+3
BiCl3
1.
BiCl3 + 3H2S
Bi2S3 Brown ppt
2.
BiCl3 + 3NH4OH
Bi(OH)3
3.
3 BiCl3 + 3H2O
+ 6 HCl
+
white PPt
3(BiO)Cl
3NH4Cl
white PPt
Preparation of Na2SnO2 :
SnCl2 + 2 NaOH
Sn(OH)2 + 2NaOH
4. 2 BiCl3 +
Sn(OH)2
excess
White ppt
+
Na2SnO2
2 NaCl
+ 2 H 2O
3Na2SnO2 + 6 NaOH
2Bi + 3Na2SnO3 + 6NaCl + 3H2O
45
Results
Reagent
H2 S
Hg+2
Cu+2
Cd+2
Bi+3
White PPt of Hg3Cl2S2
which converted into
brown and then black
in excess of H2S
KI
NH4OH
NaOH
SnCl2
KCN
KSCN
H2 O
46
Mixture of the second group
The group will be precipitated according to the solubility product.
Sulfides of the second and fourth groups have the lowest solubility
product comparing with the third,….or six group. So, the second
and fourth groups will be precipitated as sulfides while the sulfides
of other groups will be soluble.
The solubility products of the second group sulfides is less than
the solubility products of the fourth group sulfides. Therefore we
have to decrease the concentration of sulfide ion using the
common effect by using HCldil and then add H2S.
The group reagent of the second group is hydrogen sulfide (H2S).
The precipitation ion of the second group is sulfde ion.
The mixture should acidified first using HCldil (0.3 N) as a
controlling precipitation ion.
Small amount of mixture in a test tube and then add drops of
HCldil and then add H2S. If black PPt appeared then add HCldil +
H2S to the all mixture in a beaker and filter the mixture and collect
the PPt.
47
PPt (CuS , CdS, HgS, Bi2S3)
Add diluted HNO3 to the ppt and boil
All sulfides converted into soluble nitrates except HgS
Filter the mixture
Filtrate 1
Precipitate 1
May be contains Cu(NO3)2
HgS
Cd(NO3)2 , Bi(NO3)3
Dissolve the ppt in aqua regia and dilute it
and then add SnCl2, then white ppt appeared
Filtrate 1
Add NH4OH in excess
if White PPt, there is Bi
Concerning Filtrate 1,
1. If the filtrate is blue, Cu is present and then add pot. Ferro cyanide to
check.
2. Add KCN to check the presence of Cd + H2S , if yellow ppt appeared,
Cd is present.
48
Third group
Iron (Fe+3), Chromium (Cr+3), Aluminium (Al+3)
Simple salt test of Fe+3
FeCl3
1. FeCl3 + 3 NH4OH
Fe(OH)3 redish-brown ppt + 3 NH4Cl
2. FeCl3 + 3 NaOH
Fe(OH)3 redish-brown ppt + 3 NaCl
3. 2 FeCl3 + 3 (NH4)2S
Fe2S3 black ppt
4. FeCl3 + 3 K4[Fe(CN)6]
+ 6 NH4Cl
Fe4[Fe(CN)6]3 blue color + 12KCl
Ferric ferro cyanide
5. FeCl3 + K3[Fe(CN)6]
Fe[Fe(CN)6]
greenish-brown color
+ 3KCl
Ferric ferric cyanide
6. 2 FeCl3 + 6 NH4SCN
Fe[Fe(SCN)6]
red-bloody color
+ 6 NH4Cl
49
Simple salt test of Cr+3
CrCl3
1. CrCl3 + 3 NH4OH
Cr(OH)3
Green ppt
+ 3 NH4Cl
2. CrCl3 + 3 NaOH
Cr(OH) 3
Green ppt
+ 3 NaCl
Cr(OH)3
+ 3 NaOHexcess
NaCrO2
+ 2H2O
Green color of sodium chromite
3. CrCl3 + Na3PO4
CrPO4 green ppt
4. 2 CrCl3 + 3 (NH4)2S
Cr2S3
Cr2S3 + 6 H2O
2 Cr(OH)3
+ 3 NaCl
+ 6 NH4Cl
Green ppt
+ 3 H 2S
Chromium sulfide absorb moisture and form green ppt of cromium hydroxide
50
Simple salt test of Al+3
Al2(SO4)3
1. 2Al2(SO4)3 + 3 Na2CO3
Al2(CO3)3
white pp
Al2(CO3)3
+ 3 H 2O
+ 6 Na2SO4
white ppt
2Al(OH)3
white ppt
+ 3CO2
Aluminium carbonate absorb moisture and form white ppt of aluminium hydroxide
Al (OH)3
+ Na2CO3 excess
2NaAlO2 + 3H2O + CO2
Sodium aluminate
2. 2Al2(SO4)3 + 6 NH4OH
2 Al(OH)3
white ppt
+ 3(NH4)2SO4
3. 2Al2(SO4)3 + 6 NaOH
2 Al(OH)3
white ppt
+ 3Na2SO4
Al (OH)3
+ NaOH excess
2NaAlO2 + 2H2O
Sodium aluminate
4. Al2(SO4)3 + 3 (NH4)2S
Al2S3 + 3 H2O
Al2S3 + 3(NH4)2SO4
Al(OH)3
white ppt
+ 3H2S
Aluminium sulfide hydrolyzed and form white ppt of aluminium hydroxide
51
Results
Reagent
Fe+3
Cr+3
Al+3
NH4OH
NaOH
(NH4)2S
H 2S
---------------
---------------
K4[Fe(CN)6]
----------------
---------------
K3[Fe(CN)6]
---------------
--------------
NH4SCN
----------------
---------------
52
Mixture of the third group
The group will be precipitated according to the solubility product.
Hydroxides of the third group have the lowest solubility product
comparing with the fourth,….or six group.
We have to use ammonium chloride to control the hydroxide ion.
The group reagent of the third group is ammonium hydroxide
(NH4OH).
The precipitation ion of the third group is hydroxide ion.
Small amount of mixture in a test tube and then add drops of
ammonium chloride and then add ammonium hydroxide. If PPt
appeared then add ammonium chloride + ammonium hydroxide
to the all mixture in a beaker and filter the mixture and collect the
PPt.
53
PPt (Fe(OH)3 , Al(OH)3, Cr(OH)3
Add Na2O2 to the ppt to dissolve Al(OH)3 and Cr(OH)3
Filter the mixture
Filtrate 1
May be contains Na2CrO4
Precipitate 1
Fe(OH)3
and NaAlO2
1. Dissolve the Fe(OH)3 ppt in diluted HCl, and then add ammonium
thiosulfate. If bloody red color appear, the Fe is present.
2. Divide the filtrate into two portions:
To the first portion, add acetic acid and then lead acetate. If yellow
ppt appeared, Cr is present.
To the second portion, add ammonium chloride and then boil. If white
ppt appeared, Al is present.
54
Identification of acid radicals
The identification of acid radicals could be depends on the volatile
products (gases) as a result of treatment of solid sample with
acids.
Classification of acid radicals:
1. Radicals which effected with HCldil or H2SO4 dil :
Carbonate CO3-2,
Hydrogen carbonate HCO3-,
Sulfide S-2,
Thiosulfate S2O3-2,
Sulfite SO3-2,
Nitrite NO2-,
Cyanide CN-,
Cyanates CNOHypochlorite ClO2. Radicals which effected with H2SO4 conc :
Chloride Cl- ,
Bromide Br- ,
Iodide I- ,
Nitrate NO3Thiocyanate SCN-.
3. Radicals which did not effect with HCl or H2SO4 conc :
Sulfate SO4-2 ,
Phosphate PO4-3 ,
Borates BO2- , B4O7-2 , BO3-3.
55
Radicals which effected with HCldil or H2SO4 dil
Carbonate CO3-2 and Hydrogen carbonate HCO3To differentiate between carbonate and hydrogen carbonate, all
carbonate tests carried out without heating while hydrogen
carbonate happened only with heating.
1. CO3
solid salt
HCO3
solid salt
+ HCldil
Effervescence
+ HCldil
Δ
Effervescence
Na2CO3 + 2 HCl
Na HCO3 +
2NaCl + H2O + CO2 gas
HCl
Δ
NaCl + H2O + CO2 gas
CO2 gas + Ca(OH)2
CO2 excess + CaCO3
+
CaCO3
H2 O
MgCO3 white ppt
MgSO4
Δ
3. 4Na2CO3 + 4HgCl2
HgCl2
brown redish ppt
Alkali mercuric carbonate
Δ
brown redish ppt
4. Na2CO3 + 2AgNO3
Na HCO3 + AgNO3
+ Na2SO4
white ppt
3HgO.HgCO3
+ 8 NaCl + 3CO2
Na HCO3 +
+ H2O
Ca(HCO3)2 soluble
2. Na2CO3 + MgSO4
Na HCO3 +
turbidity
Ag2CO3 white ppt
Δ
+ Na NO3
white ppt
56
5. Na2CO3 + Ba(NO3)2
BaCO3 white ppt
Na HCO3 + Ba(NO3)2
Δ
+ Na NO3
white ppt
Sulfite SO3- 1. Na2SO3 solid salt + 2 HCl
2NaCl + H2O + SO2 gas
3SO2 gas + H2SO4 + K2Cr2O7
K2 SO4 + Cr2 (SO4)3
green
+ H2 O
2. Na2SO3 + AgNO3
2Ag2SO3
Ag2SO3 white ppt
Δ
Ag2SO4 + SO2
3. Na2SO3 + BaCl2
+ 2Na NO3
+ 2 Ag
BaSO3 white ppt
black
+ Na Cl
This white ppt is soluble in diluted HCl.
4. Na2SO3 + Pb(CH3COO)2
2 NaCH3COO
+ PbSO3 white ppt
This white ppt is soluble in cold diluted HNO3.
5. Na2SO3 + H2SO4
H2SO3 + 2 KMnO4
violet
H2SO3 + Na2SO4
K2SO4 + MnSO4 + 2H2SO4 + 3H2O
The violet color of potassium permanganate is disappeared.
57
Thiosulfate S2O3- 1. Na2S2O3 solid salt + 2 HCl
2NaCl + H2O + SO2 gas + S yellow
This reaction may need heating.
2. Na2S2O3 + 2AgNO3 add slowly
Ag2S2O3 + H2O
H2SO4 + Ag2S
3. Na2S2O3 + Pb(CH3COO)2
PbS2O3
white ppt
Ag2S2O3 white ppt + Na NO3
black
2 NaCH3COO + PbS2O3
+ H2O
by boiling PbS black ppt
4. Na2S2O3 + I2
white ppt
+ H2SO4
2NaI + Na2S4O6
The iodine color is disappeared.
Sulfide S- 1. Na2S solid salt + 2 HCl
2NaCl + H2Sgas
H2S turned wet paper with lead acetate into black
H2S + Pb(CH3COO)
2
2. Na2S + 2AgNO3
Ag2S black ppt
Ag2S2O3 + H2O
3. Na2S + Pb(CH3COO)
CH3COOH + PbS
H2SO4 + Ag2S
2
black ppt
+ 2Na NO3
black
2 NaCH3COO + PbS black ppt
58
Nitrite NO21. NaNO2 solid salt + HCl
3 HNO2
2 NO + O2 air
2. 2NaNO2 + 2KI + 2H2SO4
3. NaNO2 + AgNO3
NaCl + HNO2
HNO3 + H2O + 2 NO
2NO2
Na2SO4 + K2SO4 + 2NO + I2 brown + 2H2O
NaNO3 + AgNO2 white ppt
4. Brown ring experiment
2NaNO2 + H2SO4
2HNO2 + Na2SO4
3 HNO2
HNO3 + H2O + 2 NO
2 NO + FeSO4
Fe(NO)SO4
brown ring
59
Results
Reagent
CO3-2
SO3-
S2O3-2
S -2
NO2-
HCO3HCl dil
dry salt
dry salt
dry salt
Dry salt
dry salt
MgSO4
HgCl2
AgNO3
NaOH
Ba(NO3)2
(NH4)2C2O4
Tartaric acid
Bi(NO3)3
+
Na2S2O3
HClO4
NaOH
Nessler
solution
Sodium
tartarate
60
Radicals which effected with H2SO4 conc
Halides, Cl-, Br-, I1. 2NaClsolid + H2SO4 conc
2. NaBrsolid + H2SO4 conc
Na2SO4
NaHSO4
2HBr + H2SO4 conc
3. 2NaIsolid + 3 H2SO4 conc
4. NaCl + AgNO3
5. NaBr + AgNO3
6. NaI + AgNO3
+ 2HCl
Br2
+
HBr
+ 2 H2 O +
SO2
2 NaHSO4 + 2 H2O + I2 + SO2
Na2NO3
+
Na2NO3
Na2NO3
7. 2NaCl + Pb(CH3COOH)2
AgCl
+
white ppt
AgBr
+
AgI
yellowish-white ppt
yellow ppt
2CH3COONa + PbCl2
white ppt
PbCl2 is souble in hot water and precipitated again by cooling
8. 2NaBr + Pb(CH3COOH)2
2CH3COONa + PbBr2
yellowish-white ppt
PbBr2 is souble in hot water and precipitated again by cooling
9. 2NaI + Pb(CH3COOH)2
2CH3COONa + PbI2
yellow ppt
PbI2 is souble in hot water and precipitated again by cooling
10. NaCl +
Cl2
no reaction
11. NaBr +
Cl2
2NaCl + Br2
12. NaI +
Cl2
2 NaCl
+
I2
Nitrate, NO31. NaNO3 solid + H2SO4 conc
HNO3
dissociated by heating
NaHSO4
+ HNO3
2H2O + O2 + NO2
61
2. Brown ring test:
This test may by carried out using two methods:
a) Add 3ml of fresh prepared FeSO4 to 2ml of nitrate solution in a test tube.
Add 3-5ml of H2SO4 conc slowly with careful on the wall of the test tube till
two layer appeared and the brown ring formed between the two layers.
b) Add 4ml of H2SO4 conc slowly with careful to 2ml of nitrate solution in a
test tube. Mix the mixture and cool the mixture under stream of tap water.
Add fresh prepared FeSO4 slowly on the wall of the test tube till two layer
appeared and the brown ring formed between the two layers.
NaNO3
+
H2SO4
6 FeSO4 + 2 HNO3
FeSO4
+ NO
HNO3 + NaHSO4
+ 3 H2SO4
3 Fe(SO4)3 + 4 H2O + 2 NO
Fe(NO)SO4 brown ring
Nitrozel
Nitrozel compound (brown ring is unstable and dissociated by heating or
shacking and the brown ring disappeared.
62
Thiocyanate, SCN1. KSCN
solid
2. KSCN
+ 2H2SO4 conc
+ AgNO3
3. KSCN + CuSO4
yellow color and SO2 gas evolved
KNO3
K2SO4
4. 2 KSCN + Hg(NO3)2
+
AgSCN
+
white ppt
Cu(SCN)2 black ppt
Hg(SCN)2 white ppt
+
2 KNO3
Hg(SCN)2 white ppt very fast soluble in excess of mercuric nitrate.
5. KSCN
+ FeCl3
KCl
+
[Fe(SCN)] Cl2
bloody red color
The red color referred to the ion [Fe(SCN)]+++
6. 4 KSCN
+ Co(NO3)2
2 KNO3
+ K2[Co(SCN)4]
blue color
63
Results
Reagent
Cl-
H2SO4 conc
dry salt
Brdry salt
Idry salt
NO3 Dry salt
SCNdry salt
AgNO3
HgCl2
Cl2
Pb(CH3COO)2
CuSO4
Brown ring
Hg(NO3)2
FeCl3
Co(NO3)2
64
Classifications Of Basic Radicals
Group
Group reagent
Ions
Formula of precipitate
Distinguishing features
I
Dilute HCl
Ag+, Pb+2, Hg2+2
AgCl, PbCl2, Hg2Cl2
Chlorides insoluble in cold
Silver group
dilute HCl
II
H2S in presence of
Hg+2, Pb+2, Bi+3,
Copper and
dilute HCl
Cu+2, Cd+2, Sn+2,
CuS, CdS, SnS,
As+3, Sb+3, Sn+4 ,
As2S3, Sb2S3, SnS2 , As2S5
Arsenic group
HgS, PbS,
Bi2S3,
Sulfides insoluble in dilute
HCl
As+5
III
NH4OH in presence
Al+3, Cr+3, Fe+2,
Al(OH)3, Cr(OH)3, Fe(OH)2,
Iron group
of NH4Cl
Fe+3
Fe(OH)3
IV
H2S in presence of
Ni+2, Co+2, Mn+2,
NiS, CoS, MnS,
Zinc group
NH4OH, NH4Cl
Zn+2
ZnS
V
(NH4)2CO3 in
Ca+2, Sr+2, Ba+2
CaCO3, SrCO3, BaCO3
Carbonates PPt
Calcium group
presence of NH4OH,
Mg+2, Na+, K+,
-----------
------------
Hydroxides PPt
Sulfides PPt
NH4Cl
VI
Alkali group
No group reagent
NH4+
65
