Qualitative analysis

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QUALITATIVE ANALYSIS
What is qualitative analysis?
Qualitative analysis is the analysis which deals with the determination or identification of
the components of the unknown given chemical solid substance. The unknown chemical solid
substance actually we talk about the solid salt which normally we are given but the name is
unknown. The solid salt is placed into the watch-glass, then you are required to identify “cation”
and “Anion” then chemical formula of the salt
SOLID SAMPLE [unknown salt]
This is the solid salt which contains the ions which you are required to identify.
Consider the solid salt in the watch glass below;
ION(S)
This is the positively or negatively charged particle formed by the Electron loss or gain by
atom/element
TYPES OF IONS
There are two types
Cation e.g. NH4
+, Na+, K+, Mg2+, Pb2+ etc
Anion e.g SO4
2-, HSO4
-, CO3
2-, HCO3
-, NO3
-, CL- etc
NOTE;

CATION; is the positively charged particle formed by the Electron loss by an atom/Element.
Example;
NH4
+, Ca2+, Zn2+, Pb2+, Mg2+, K+ etc
ANION; is the negatively charged particle formed by the Electron gain by an atom/Element.
Example;
SO4
2-, HSO4
- - Bisulphate/ Hydrogen sulphate
Cl-, NO3
-, HCO3
- - Bicarbonate/ Hydrogen carbonate
CO3
2-, C2O4
2-, S2O3
2-, SO3
- etc
QUALITATIVE GUIDE SHEET (QDS)
-This is the sheet which contains the information used or guiding in order to answer the
Qualitative analysis questions. Normally in the Examinations room you are provided with this
sheet. Consider how the sheet appears and it includes .experiment, observation and Inference.
S/N EXPERIMENT OBSERVATION INFERENCE
a)
Appearance of the sample e.g. Take
the sample then observe its
appearance and texture
Salt was ‘Blue’
crystalline solid
Cu2+ may be present
Salt was ‘Green’
crystalline solid
Fe2+ may be present
Salt was ‘White’
crystalline solid
NH4
+,Na+, K+, Al3+,
Mg2+, Pb2+, Zn2+ may
be present
Salt was white
powdered solid
CO3
2- of Zn2+, Pb2+
may be present
b)
Solubility- take the solid salt put into
the test tube then add distilled water
Salt was soluble
Soluble salt was
present NO3
-, Cl-, SO4
2-
, CO3
2- etc
EXPERIMENT
This is the practically done action by the experimenter.
An Experimenter can

(i)Take the salt sample from Watch glass then;-
Observe its colour
Salt solid sample observed on the hand by observer, the colour of the sample must be stated.
E.g. Blue- Cu2+, red- Cu+, green- Fe2+, Fe3+ - brown/yellow, White- NH4
+, Na+, Zn2+, Pb2+, K+ etc
Check the texture of the salt.
Smell the salt or its odor
Dissolve it into the distilled water into the test then observe if soluble or not soluble (insoluble).
OBSERVATION
This is what an experimenter has seen due to the Experiment which he/she had performed.
The following are the common or possible observation which an experimenter can observe
1. Powdered/crystalline solid sample
2. The colour E.g. Green, yellow, white.
3. Evolution of the gas e.g. O2, NH3, NO2,SO2
4. Formation of the ppt( precipitation)/(precipitate)
5. The colour of Residue formed after heating the solid sample.
6. The smell of the solid sample E.g. Urine (NH3)smells irritating chocking smell
7. Solubility of the salt if soluble/insoluble.
Note;
On doing the solubility leave the salt to stay for certain period of time, because some of
the salt takes the time to dissolve completely. Don’t harry up to state that the salt is Insoluble.
INFERENCE (conclusion)
This is the stage which an experimenter is required to take the conclusion above the
result observed after doing an experiment.
EXPERIMENT OBSERVATION INFERENCE
Action of heat of salt TT
Gas with urine smell produced
Gas – NH3
NH4
+was confirmed

Action of con. H2SO4 on solid salt
TT
Reddish brown/yellow fumes
was observed
Gas –NO2
NO3
- was confirmed.
Conclusion; cation NH4
+ Anion –NO3
- formula of TT –NH4NO3
TYPES OF QUALITATIVE ANALYSIS
There are;-
i./Guided Qualitative Analysis
Ii./Systematic Qualitative Analysis (unguided)
GUIDED QUALITATIVE ANALYSIS
-Is the type of Qualitative which the experiments to be done by an experimenter is guided
or instructed or limited.
POSSIBLE QUESTION
The salt sample WW contains one cation and Anion in the tabular form of Experiment,
Observation and Inference Identify cation and Anion in the salt solid sample WW.
a) Take the sample WW
then observe it
b) Take one spatula full of
solid sample WW then smell it
c) Take the salt WW put it
into the clean test tube then add
distilled water until half of test
tube
d) To the solid sample WW
add
1. Dil. HCL

2. Conc. H2SO4
Conclusion Cation – Anion- Formula of WW
SYSTEMATIC QUALITATIVE ANALYSIS
-Is the type of the qualitative analysis which no instructions is given but an experimenter should
follow the procedures/stages which can led to identification of solid sample
POSSIBLE QUESTION
The salt sample WW contains one cation and Anion in the tabular form below identifies cation,
Anion and formula of WW.
SOLN/ ANS:
a)
Appearance of the sample
WW
Solid sample WW was
white crystal solid
NH4
+, Na+, zn2+, Pb2+,
Ca2+, Mg2+, Al3+, may
be present
b) Smell of sample WW
The sample gave smell of
Ammonia gas (urine)
... Gas- NH3
NH4
+ was present and
confirmed
c) Solubility of WW
The sample was soluble
and formed clear solution
Soluble salt may be
present NO3
-, Cl-, SO4
2-,
CO3
2-, HCO3
-, except
AgCl, Baso4, ZnCO3,
PbCO3
d)
Action of dil. H2SO4 to solid
WW
Gas with Urine smell
detected
NH4
+ confirmed
e)
Action of dil. NAOH solution
to WW solution
Gas with urine system
detected
NH4
+ confirmed
f)
Action of Bacl2 to WW
solution
White ppt was formed SO4
2- confirmed

Conclusion: Cation NH4
+ Anion SO4
2- formula (NH4)2SO4
STAGES OF SYSTEMATIC QUALITATIVE ANALYSIS
They include;-
-Preliminary test
-Test in solution
-Confirmatory test
PRELIMINARY TEST
These are the tests which are done at the first stage such that preliminary information of the
solid sample can be obtained;-
These Experiments includes;
1. Appearance of the sample (solid)
Here we talk about colour, Texture of sample,
2. Solubility of the sample (solid)
3. Smell of the solid sample
4. Action of heat on solid sample
5. Action of dil. HCl (Hydrochloric Acid) or concentrated sulphuric Acid (con.H2SO4)on the
solid sample into test tube(TT)
6. Flame test of solid sample
7. Residue test of the solid sample
THE REQUIREMENTS;
a. Clean test tubes

b. Test tube holder
C. Heat source e.g. Bunsen burner
d. Distilled Water E.g.

e.) Acid E.g.
APPEARANCE OF SOLID SAMPLE
Rewind or Recall from periodic table.
POSSIBLE QUESTION

a)
Appearance of a solid
sample
Sample BB was white
crystalline solid
Transitional elements
(Fe2+, Fe3+, Cu2+) absent
Sample BB was light green
crystalline solid
Fe2+ or Cu2+ may be
present
b) Appearance of RR
Sample RR was blue in
color
Cu2+ may be present
Sample RR was yellow in
color
Fe3+ may be present
SOLUBILITY OF SOLID SAMPLE
Take solid sample put small (little) amount into clean test tube then Add distilled Water into the
solid sample observe it if soluble or insoluble. Be careful on observing
E.g. salt -AA or CC or TT etc
Note;
Transition metals [Cu2+,Cu+, Fe3+] they tend to display [show] their colour if their salt dissolved
into Water provided that they are soluble-salt.
COLOR OF SOLUTION FORMED ON DISSOLVING SALT SAMPLE IN WATER.
-Consider the table below for more illustration;
E.g. SALT SAMPLE

Pata pdf za masomo kwa bei rahisi o level somo 2000 na a level 3000 whatsapp 0673856460 Page
10
POSSIBLE QUESTION
a) Solubility of sample QQ
1.
Cu2+ may be present
b) 2.
Colored solution was formed
Transition metals Cu2+,
Fe2+, Fe3+may be present
Colorless solution was formed
Soluble salt of NH4
+,
Na+, Ca2+, Pb2+, Zn2+,
K+, Al3+ may be present
Fill (i) and (ii)
Answer
1. Blue solution was formed
2. Solubility of a sample
SMELL OF THE SOLID SAMPLE
Take the solid sample then smell it. Normally Ammonium salt -NH4
+ Even at the room-
temperature they tend to give out the Urine smell (smell of Ammonia gas –NH3 or When they
are Heated (âˆ†). But other salts are (odorless) E.g. Don’t give out the smell , salt of Na+,Cu2+,
Zn2+,Pb2+,Ba2+,Mg2+,K+ .etc.
TABLE OF RESULTS
OBSERVATION INFERENCE
Salt had the irritating chocking smell (Urine
smell) or smell of Ammonia gas
NH4
+ is confirmed
No specific smell detected or salt had no any
smell
NH4
+ was absent or Na+, Ca2+, Al3+, Zn2+, Pb2+,
Mg2+, K+ may be present
POSSIBLE QUESTION

11
a)
On smelling the sample XX
into a watch glass
Ammonia gas smell was
detected
i)
ii) NH4
+ was absent
b) Urine smell detected NH4
+ confirmed
Fill (i), (ii), (b)
Ans (i) NH4
+ confirmed (ii) no specific smell detected (b) Smell of the sample
NATURE OF GASES, SMELL, ACTION OF LITMUS, COLOR, SOLUBILITY
 Some of the gases are Acidic, Basic (Alkaline), colorless, colored, soluble, insoluble have
smell (odor), odorless.
GAS SMELL NATURE COLOR SOLUBILITY
ACTION ON
LITMUS
NH3 Urine or Basic/alkaline colorless Highly soluble Blue
NO2 Pungent Acidic Reddish soluble Red
So2
smell Brown/yellow soluble Red
Irritating Acidic colorless soluble
cl2 Irritating Acidic Greenish soluble Red then
yellow bleached
CO2 odorless Acidic colorless soluble Red
O2 odorless Neutral colorless insoluble No
Note: We can try to know the nature of the gas by dissolving it into Water then resulting solution
may be Acidic, Basic, or Neutral. E.g.
1. NH3 + H2O →NH4OH - Base/Alkaline
2. CO2 + H2O→H2CO3 - Acid
3. NO2 + H2O→HNO3 - Acid
4. Cl2 + H2O→ HClO + HCl - Acid
5. SO3 +H2O→H2SO4 - Acid
6. SO2 + H2O→H2SO3 - Acid

12
ACTION OF HEAT ON SOLID SAMPLE IN THE DRY AND CLEAN TEST
TUBE
To the clean, dry test tube put the salt sample then heat it for few minutes and observe the
changes which occur some of the salt are stable(under composes) but other decomposes(stable)
During heating process you can observe the colour if gas Evolved, smell of the Gas Evolved.
Normally each radical releases
Example
SALT RADICAL + HEAT → GAS EVOLVED + RESIDUE
You have been given with salt sample AA, PP, QQ, NN, ZZ, and TT.

13

14
POSSIBLE QUESTION
You have been given with salt sample ZZ, QQ, Which was the piece of the paper isolated in the
Examination room by form IV students at Mtazamo secondary school.
The salt ZZ gave the yellow residue- hot and
White-Residual-GG cold and Reddish brown

15
yellow fumes of the gas PP.
The salt QQ gave the colorless gas – FF Which
turn lime water – Ca(oH2) to milky form and
Extinguishing the fire or burning candle the gas
produced the Effervescence and turned damp
litmus-Blue paper Red and yellow Residue HH.
a. Fill the inference column
b. Given cation - Anion and formula of salt ZZ including cation -Anion -in QQ
c. Name gas FF, PP, Residue HH, GG.
INFERENCE
1
2.
No3
- confirmed
Co3
2-/HCO3
-
May be was present
b. Cation - Zn2+, Anion-No3
- formula Zn (NO3)2 OF ZZ cation -Pb2+ Anion - CO3
2-
/HCO3
-
c. FF- Nitrogen dioxide – NO2
PP-Carbon dioxide – CO2
HH – Lead oxide (PbO),
GG- zinc oxide (ZnO)

16
HOW TO IDENTIFY THE GAS EVOLVED DURING EXPERIMENT [Heating
using Acid]
The following methods can be used;-
1. Through smelling
2. By using the damp litmus paper
3. By observing the colour of gas
4. Experiments

17
FLAME TEST [Give the cation E .g Pb2+ Cu2+,Na+etc
→The Nichrome wire or glass rod or Test tube then dip into the test-tube containing dil. HCl the
reason; Is to provide White vapour on the flame on heating the salt. Take the Wet nichrome or
glass rod or test tube dip into the salt sample, so the salt sample should stuck on the Wire.
Transfer the salt on the flame burn it While observing the colour given by the flame.

18

19
OBSERVATIONS;
Example Blue- Green flame – Cu2+, Green flame-Fe2+,yellow spark-Fe3+,Golden yellow flame-
Na+, Lilac/Purple flame-K+, Blue flame – Pb2+,Brickred flame- Ca2+, No specific flame
Zn2+,Al3+, Mg2+.
PROCEDURES OF THE FLAME TEST
Refer the diagram below
Consider the diagrams below showing how to perform Flame test

20
Green-Apple flame/colour action Ba2+ confirmed
Green flame Fe2+ confirmed
Blue- Green flame Cu2+confirmed
Golden yellow flame Na2+ confirmed
Yellow sparks Fe3+ confirmed
Blue/Bluish flame Pb2+ confirmed
ACTION OF DILUTE HCl, HNO3 OR CONCENTRATED SULPHURIC ACID
[con.H2SO4] ON SOLID SALT IN DRY AND CLEAN TEST TUBE
Take the solid salt put into the clean and dry test tube, and then Add either dilute HCl or
con.H2SO4 or dil.HNO3 then observe what happened. Hydrochloric acid –HCl, Nitric Acid –
HNO3 and
H2SO4have the tendency to break down radical such as CO3
2- ORHCO3
- then form CO2- carbon
dioxide which give off Effervescence. But on additional of con.H2SO4or HNO3 (dil) or dil. HCl
to the salt which have no Co3
2-/HCO3
- No Co2. Evolved probably other gas

21
PROCEDURES DURING ACTION OF ACID ON SOLID SAMPLE [SALT] BY USING
ACID
[Dil. HCL, H2SO4, dil.HNO3]
You have been given with salt JJ, KK, and LL . examples ACIDS ADDED TO SOLID
SALT

22
RESIDUE TEST [Identify cation Example Zn2+, Cu2+ etc.
Take the given salt sample put it into the test tube then heat until no changes occurs. The test
tube should be clean and dry on doing the residue test. Note that some of the salt doesn’t
decompose.

23
 These salt – CO3
2- of group I (alkaline metal) are stable on heating so they don’t
decompose at all
 These salt of group II (Alkaline metal) their Sulphates - SO4
2- are very stable
Illustration
OBSERVATION;
1. Blue- Residue turn black- CuO cation- Cu2+
2. No colour E.g. MgO , Al2O3 etc
PROCEDURES FOR THE RESIDUE TEST

24
You have been given with salt sample solid WW, MM and TT.
Residue was;-WW
Yellow -hot but on cooling (cold) - turn
white
Residue WW - ZnO
↓
Cation → Zn2+
Zn2+ confirmed
Residue MM was ;-
Yellow-cold and white-hot
Residue MM- PbO
↓
Pb2+ confirmed

25
Pb2+
POSSIBLE QUESTION
Solid PP was White on heating gave yellow â”€ Residue When hot on cooling become
White PP was;-
1. ZnCO3
2. ZnO
3. ZnCl2
TEST IN THE SOLUTION
This is the second stage of the Qualitative analysis which the test is done in the solution
form.
Example –Take the salt given then put iit into the beaker or Test tube then add distilled water in
order to obtain the solution.
Note; AA – Known as mother solution (M.s) or stock solution/original solution
Then you can divide the solution into the different solutions E.g. First solution, second solution
Third solution, then you can add given reagent such as NaOH, NH4OH etc

26
NaOH +CuCl2→CU (OH) 2 + Nacl
 NH4OH + Cuso4→ Deep – Blue ppt
NH4OH + Cuso4→ Cu (OH )2 + (NH4)2SO4
 NaOH + solution → Green ppt -Fe2+
NaOH + Fe (NO3)2 → Fe (OH)2 + HNO3
OBSERVATION;
Brown ppt -Fe3, Na+, Ca2+, NH4
+, K+ White ppt
PROCEDURES DURING THE TEST IN SOLUTION
You have been given with the salt RR, FF.

27
Take the salt dissolve into the given distilled water in order to obtain the solution. This solution
can be divided into the different solution named first, second, third etc.
The following solution, solution (reagent) can be Added to the prepared solution;-
1. Sodium hydroxide – NaOH
2. Ammonium hydroxide / Aqueous solution - NH4OH
3. Potassium hexaferrocynide
S/N OBSERVATION INFERENCE
Deep blue ppt Cu2+ confirmed
Green ppt Fe2+ confirmed
Brown ppt Fe3+ confirmed
White ppt Na+, Ca2+, Al3+, K+ confirmed

28
THE MAIN AIM OF THE ADDITIONAL OF SODIUM HYDROXIDE â”€NaOH or
NH4OH TO THE ORIGINAL SOLUTION (O.S) or STOCK SOLUTION (S.S) OR
MOTHER SOLUTION (M.S)
The aim is to identify the cation in the solution given, and then observe what occurred into
the solution you make.
CONFIRMATORY TEST
This is the third stage and lastly stage of the Qualitative analysis which can be used to determine
or identify the specific cation or Anion present in the unknown given salt. Each cation or Anion
has the specific confirmatory reagent used to identify them.
E.g. IDENTIFICATION OF ANION
To a sample solution AgNO3 is
added followed by dil. HNO3
solution then excess ammonia
solution
White ppt insoluble in HNO3
but soluble in ammonia
solution
Cl- present and confirmed
A sample solid is mixed with
manganese dioxide and conc.
H2SO4 added and warmed
Greenish yellow gas with a
pungent smell is (Cl2) is given
out which turn a moist Kl-
starch paper blue
Cl- present and confirmed
To a solution of sample dil.
HCl is added followed by
BaCl2 solution
White ppt insoluble dil. HCl is
formed
SO4
-2 present and confirmed
To a sample solution add fresh
prepared ferrous sulphate
solution followed by carefully
addition of conc. H2SO4 along
the side of the test tube
Brown ring is formed NO-3 present and confirmed
For insoluble carbonate add dil.
HCl
colourless gas forming lime
water milky effervescence
evolved
CO3
To a sample solution in water
MgSO4 is added, boiled if ppt
White ppt in cold CO3
White ppt after warming HCO3
- present and confirmed

29
not formed
(i)In-A-Solution

30
(ii)In-D-Solution
COMMON SALTS IN THE QUALITATIVE ANALYSIS
You must be familiar with the following salts
(a)Ammonium salts
Example;
1. Ammonium chloride - NH4Cl
2. Ammonium Nitrate - NH4NO3
3. Ammonium sulphate - (NH4)2SO4 etc
(b) Iron salts
Example;
1. Iron II chloride - FeCl2
2. Iron III chloride - FeCl3
3. Iron II sulphate - FeSO4
(c) Calcium salts

31
Example;
1. Calcium chloride -CaCl2
2. Calcium carbonate - CaCO3
(d)Sodium salts
Example;
1. Sodium carbonate - Na2CO3
2. Sodium bicarbonate - NaHCO3
3. Sodium sulphate - Na2SO4
4. Sodium Nitrate - NaNO3
5. Sodium chloride - NaCl
(e)Zinc salts
Example;
1. Zinc carbonate - ZnCO3
2. Zinc sulphate - ZnSO4
(f)Copper salts
Example;
 Copper II sulphate -CuSO4
 Copper II chloride -CuCl2
 Copper II Nitrate -Cu(NO3)2
 Copper I sulphate - Cu2SO4
(g) Lead salts
 Lead chloride - PbCl2
 Lead Nitrate - Pb(NO3)2
 Lead sulphate - PbSO4
(h) Potassium salts
 Potassium chloride - KCl
 Potassium carbonate - K2CO3

32
NOTE
You should be able to;-
-Use the qualitative Analysis sheet
-Know the Appearance of the salt
-Know the flame test
-Identify the cation, Anion
-Know how to write down the chemical formula of the compound.
-Write down the balanced chemical Equation Which take place or occur during practical
-Prepare the solution of the salt etc

Qualitative analysis

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