qualitative analysis sheet for o level chemistry

ALI SULEIMAN ALI (ALSAL) @ HIGH QUALITY TUITION CENTRE.

2016-2020

QUALITATIVE ANALYSIS

SHEET FOR O-LEVEL CHEMISTRY

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HIGH QUALITY TUITION CENTRE MAGOGONI ZANZIBAR.

of 13 ALI SULEIMAN ALI (ALSAL) @ HIGH QUALITY TUITION CENTRE

QUALITATIVE ANALYSIS SHEET

INTRODUCTION

This qualitative analysis sheet is designed to solve for Ordinary level qualitatively analysis

practical in which all ions (anion and cat ion) mentioned in the Ordinary level chemistry

syllabus will be designed by using available reagent.

In qualitative analysis we ready find out the composition of the compound or the mixture of

the compounds. This will involve the identification of the Cations( basic radicals or metallic

radicals) and Anions (acidic radicals or non-metallic radicals)

The Cat ions and Anions required in this qualitative analysis are as follow: -

CATIONS SYMBOLS ANIONS SYMBOLS

Ammonium ion NH4+ Bicarbonate ion HCO3

-

Calcium ion Ca2+ Chloride ion Cl-

Copper (ii) ion Cu2+ Carbonate ion CO32-

Iron (ii) ion Fe2+ Nitrate ion NO3-

Iron (iii) ion Fe3+ Sulfate ion SO42-

Lead (ii) ion Pb2+ Sulfite ion SO32-

Sodium ion Na+ Sulfide ion SO22-

Zinc ion Zn2+

In analysis the salt,you are required to follow the following systematically qualitatively

analysis procedures:-

1. Appearance

2. Solubility of the salt in water

3. Action of heat

4. Action of dilute acid

5. Action of concentrated sulfuric acid

6. Confirmatory test for Anions (Basic radicals)

7. Action of sodium hydroxide

8. Action of Ammonium hydroxide

9. Confirmatory test for Cat ions (Acidic radical)

10. Conclusion



General properties of ions

1. Solubility of compound in water

CATION/

ANIONS

Na+& K+ Ca2+ NH4+ Zn2+ Cu2+ Fe2+ & Fe3+ Pb2+

CO32- √ X √ X X X X

SO42- √ O √ √ √ √ X

NO3- √ √ √ √ √ √ √

OH- √ O No action X X X X

Cl- √ √ √ √ √ √ O

√-Soluble

X-Insoluble

O-Sparingly slightly soluble

2. Action of heat

CATION/

ANIONS

Na+& K+ Ca2+ NH4+ Zn2+ Cu2+ Fe2+ & Fe3+ Pb2+

CO32- X √ √ √ √ √ √

SO42- X X √ X X √ X

NO3- √ √ O √ √ O √ √

OH- O O O O √ O √ O

Cl- O O √ O O O O

√-Decompose

X-Does not decompose

O-Does not exist

1. APPEARANCE

Examine the physical properties of the given substance

Example Nature , Color , Smell all come under one heading APPEARANCE.

NATURE

The following can be inferred from the nature of the salt sample:-

OBSERVATION INFERENCE

Crystalline Cl-, NO3-,SO3

2-,HCO3-, or certain SO4

2-or CO32-

Powder CO32-,S2-or certain SO4

2-

COLOR


Black Suggest S2- of Pb2+,Cu2+,Fe2+or O2- of Cu2+

Green Suggest Fe2+ or Cu2+

Yellow Suggest Pb2+ or Fe3+

White Suggest Na+,NH4+,Ca2+,Pb2+ or Zn2+

Blue Suggest Cu2+

Brown Suggest Pb2O4 or Fe3+



SMELL


Rotten egg smell Suggest S2-

Pungent smell Suggest NH4+

Example

EXPERIMENT OBSERVATION INFERENCE

Appearance Blue crystals with no smell Suggest NO3-or SO4

2-of Cu2+

2. SOLUBILITY OF A SUBSTANCE IN WATER

Take a little substance in a test tube and add distilled water and shake the mixture if

the salt is insoluble heat the mixture.


Substance soluble in water and give clear

solution

Suggest NO3-,Cl-,HCO3

-,SO32-or certain

SO42-or certain CO3

2- of ………….

Clear colorless solution Fe2+,Cu2+,Fe3+ absence

Clear greenish solution Fe2+,Cu2+ present

Clear yellowish solution Fe3+ present

Clear blue solution Cu2+ present

Substance insoluble in cold and hot water Suggest CO32-,S2-, or certain SO4

2-

Substance insoluble in cold water but

soluble in hot water

Suggest PbCl2

3. ACTION OF HEAT

Put a small quantity of the original substance (O.S) in a clean and dry test tube and

heat.

NOTE: If a gas evolves identify it, or note any sublimation take place and the color

change from the original substance (O.S) to the remaining residue


Substance sublimed with no residue Suggest NH4+

Colorless gas with pungent smell evolves. The gas turned damp

red litmus paper to blue and formed dense white fumes with

Hydrogen chloride.

Suggest NH4+ and the gas

was NH3(g)

Brown fumes evolved and turned damp blue litmus to red Suggest NO3-,The gas

was NO2(g)

Colorless gas evolved turned damp blue litmus to red and turned

lime water to milky.

Suggest CO32-or HCO3

-

the gas was CO2(g)

Colorless gas evolved with irritating smell. The gas turned blue

litmus paper to red and bleached it. The gas also turned K2Cr2O7

paper from yellow to green and decolorize KMnO4 solution.

Suggest SO32-or SO4

2-or

S2O32-

Colorless gas evolved which rekindled a glowing splint of fire Suggest NO3- of Na+ or

K+ The gas was O2(g)

Water vapor is given off and condensed on the coolant part of the

test tube.

Suggest Hydrated salt

No gas evolved and no residue is formed Suggest Cl- absence of

NO3-,SO4

2-or CO32-



Also consider the following


The color of the salt turned from blue to white after heating Suggest CuSO4:5H2O

The color of the salt changed from green to black after being

heated.

Suggest Cu2+.The residue

was CuO.

The color of the salt turned from pale green to white and

finally to reddish brown and dense white fumes evolved

which turned damp blue litmus to red, decolorized KMnO4

and turned K2Cr2O7from yellow to green.

Suggest FeSO4:7H2O.The

residue was Fe2O3.The

gas were SO3(g) and

SO2(g).

Residue yellow when hot and white when cool. Suggest Zn2+ salt present

and the residue was ZnO.

Residue brown when hot and yellow when cool. Suggest Pb2+ salt present

and the residue was PbO.

The color of the salt turned from yellow to brown after

heated.

Suggest Fe3+

4. ACTION OF DILUTE HYDROCHLORIC ACID

Take a little amount of the original substance in a clean and dry test tube and add little

dilute Hydrochloric acid. If there is no reaction warm the mixture but do not boil. If

the gas evolved identify it.


Vigorous reaction occurred in cold dilute acid. Colorless gas

evolved. The gas turned damp blue litmus to red and lime

water to milky.

Suggest CO32- or

HCO3- . The gas was

CO2(g).

Colorless gas with rotten egg smell evolved. The gas turned

damp blue litmus to red and Lead acetate paper to black.

Suggest S2-.The gas

was H2S(g).

Colorless gas evolved with irritating smell, The gas changed

damp blue litmus paper to red change K2Cr2O7 paper from

yellow to green and decolorize KMnO4.

Suggest SO32-. The gas

was SO2(g)

N.BIf no gas evolved with cold and warmed dilute Hydrochloric acid and clean

solution formed, add Barium chloride solution to the clear solution obtained.


No gas evolved in cold and warmed dilute HCl.While

precipitates formed with Barium chloride solution and

insoluble in excess dilute HCl acid.

Suggest SO42-

Neither gas evolved on cold and warmed dilute HCl

acid no precipitations formed with Barium chloride

and the solution remained clear

Suggest NO3- or Cl-

Colorless gas with irritating smell evolved, the gas

turned damp blue litmus paper to red and bleach it and

also turned K2Cr2O7 paper from yellow to green with

yellow deposition residue.

Suggest S2O32- . The residue

was Sulfur and the gas was

SO2(g).

Colorless gas with chocking smell of vinegar evolved,

the gas turn damp blue litmus paper to red.

Suggest CH3COO-



5. ACTION OF CONCENTRATION SULFURIC ACID

Take a little amount from the original substance in a dry test tube and carefully add

concentrated sulfuric acid. If there is no reaction warm the mixture but do not boil,

and identify the gas.


Vigorous reaction on cold acid, colorless gas evolved

and turned damp blue litmus paper to red and lime water

to milky

Suggest CO32-,or HCO3

-

.The gas was CO2(g).

Misty fumes forming colorless gas evolved on cold acid

with strongly fumes in air. The gas turned damp blue

litmus paper to red and forms denser white fumes with

Ammonia solution. Mixture gave yellowish green gas

when warmed with MnO2 or PbO2.

Suggest Cl- .The gas was

HCl(g) and yellowish green

gas was Cl(g).

Effervescence, colorless gas with rotten egg smell

evolved on cold acid. The gas turned damp blue litmus

paper to red and Lead acetate paper to black.

Suggest S2-. The gas was

H2S(g).

Vigorous reaction occurred colorless gas with irritating

smell evolved, The gas turned damp blue litmus paper to

red and bleach it. The gas turned K2Cr2O7 paper to green

and decolorize KMnO4 with deposition of yellow

residue.

Suggest SO32- or S2O3

2- .

The gas was SO2(g) and

yellow deposition was

sulfur S(s).

Pungent brown fumes evolved on strong warming and

turned damp blue litmus paper to red.

Suggest NO3-.The gas was

NO2(g).

No gas evolved on cold and warmed concentration

sulfuric acid.

Suggest SO42-.

Colorless gas with a chocking smell of vinegar. The gas

turned damp blue litmus paper to pale blue.

Suggest CH3COO-

PREPARATION OF THE SOLUTION

i. Take a little amount from original substance in a clean test tube and fill half

full of it with distilled water, shake vigorously. Warm if necessary.

If the substance dissolved in cold warm water use the solution obtained to

identify Anion and Cat ion.

ii. If the substance did not dissolve in cold and warmed distilled water use dilute

Hydrochloric acid to make the solution and use it for identification.

iii. If the substance still remained insoluble make a solution of this substance by

using dilute Nitric acid. Filter the result solution and use the portion from the

filtrate for the following tests.

6. CONFIMATORY TESTS FOR ANION (ACIDIC RADICALS)

a. SULFATE

Toa solution suspected of sulfate add few drops of Barium chloride solution

then add dilute Hydrochloric acid in excess.


White precipitate insoluble in excess dilute HCl Confirm SO42- Present



b. SULFITE

To the solution suspected contained sulfite add few drops of Barium Chloride

then add dilute Hydrochloric acid to the excess.


White precipitate soluble in excess dilute HCl Confirm SO32- Present

c. CHLORIDE

i. To the solution suspected of Chloride add few drops of Silver Nitrate

solution then add dilute Nitric acid in excess


White precipitate formed with AgNO3 solution insoluble in

excess dilute HNO3 acid but soluble in excess ammonia

solution

Confirm Cl- Present

ii. Add Manganese dioxide to the test tube containing O.S and add

concentrated H2SO4 then heat.


Evolution of the greenish yellow gas with MnO2 and conc.

H2SO4. The gas turned damp blue litmus paper to red.

Confirm Cl- Present

d. NITRATE

i. To the solution suspected of Nitrate add freshly prepared Ferrous

Sulfate solution then tilt the test tube at an angle and add slowly and

carefully concentrated Sulfuric acid down the side of the test tube so

that it sinks to the bottom of the test tube.


Brown ring formed at the function on addition of freshly

prepared FeSO4 and addition of conc. H2SO4.

Confirm NO3- Present

ii. Add Copper chips to the test tube containing O.S and concentrated

H2SO4 then warm.


Brown fumes evolved with copper chips and conc.

H2SO4.The fumes turned damp blue litmus paper to red.

Confirm NO3- Present

e. CARBONATE

i. Add Magnesium Sulfate or Calcium Chloride solution to the solution

suspected of Carbonate.


White precipitate formed immediately on addition of

Calcium Chloride.

Confirm CO32- Present

N.BThis test for the soluble Carbonate only



ii. Take a little of the O.S in the test tube and add dilute HCl.


Colorless gas evolved with dilute HCl which turned damp

blue litmus paper to red and lime water to milky

Confirm CO32- Present

f. HYDROGEN CARBONATE ( BICARBONATE )

To a solution suspected of Bicarbonate, add Magnesium Sulfate solution


No precipitates were formed with MgSO4 solution. Confirm HCO3- Present

g. SULFIDE

To the solution suspected of Sulfide, add dilute HCl acid and warm gently.


Colorless gas with rotten egg smell evolved in warmed dilute

HCl. The gas turned blue litmus paper to red and Lead acetate

paper to black.

Confirm S2- Present

IDENTIFICATION OF CATIONS ( METALLIC RADICALS ) 7. ACTION OF SODIUM HYDROXIDE SOLUTION.

To a little of the solution prepared in a test tube add Sodium Hydroxide drop by drop

till the alkaline is in excess.

If there is no reaction warms gently but do not boil.


To a solution with NaOH solution, colorless gas

evolved with pungent smell and turned red litmus

paper to blue.

Suggest NH4+ present.

To a solution with NaOH solution, white

precipitates formed insoluble in excess alkaline.

Suggest Ca2+ present

To a solution with NaOH solution, pale blue

precipitate insoluble in excess alkaline.

Suggest Cu2+ present

To a solution with NaOH solution, dirty green

gelatinous precipitates insoluble in excess alkaline.

Suggest Fe2+ present

To a solution with NaOHsolution, reddish brown

precipitates insoluble in excess alkaline.


To a solution with NaOHsolution, white gelatinous

soluble in excess alkaline.

Suggest Zn2+ or Pb2+ presents



8. ACTION OF AMMONIUM HYDROXIDE SOLUTION

Take a little portion of the solution in test tube and add Ammonium solution drop by

drop till in excess alkaline.


To a solution with NH4OH solution, white gelatinous

precipitates insoluble in excess alkalis

Suggest Ca2+ or Pb2+ presents

To a solution with NH4OH solution, white gelatinous

precipitates soluble in excess alkalis.

Suggest Zn2+ present

To a solution with NH4OH solution, pale blue precipitates

soluble in excess alkalis and formed deep blue solution.

Suggest Cu2+ present

To a solution with NH4OH solution, dirty green precipitates

insoluble in excess alkalis.


To a solution with NH4OHsolution, reddish brown

precipitates insoluble in excess alkalis.


To a solution with NH4OH solution, no precipitates formed. Suggest NH4+ present

9. CONFIMATORY TEST FOR CATIONS ( METTALIC RADICALS )

a. COPPER

i. To a solution suspected of Copper salt, add little Potassium Ferro

cyanide solution.


Brown precipitates formed with Potassium Ferro cyanide

solution.

Confirm Cu2+ Present

ii. To a solution suspected of Copper salt add little Ammonium Sulfate

solution.


Brownish black precipitates formed with Ammonium Sulfate

solution.

Confirm Cu2+ Present

b. LEAD

i. To a little of the solution contained Lead salt add dilute Sulfuric acid

drop by drop with shaking.


White precipitates formed with dilute H2SO4 Confirm Pb2+ Present



ii. To a solution suspected of Lead salt add Potassium Chromate solution

drop by drop with shaking.


Yellow precipitates formed with Potassium chromate solution. Confirm Pb2+ Present

iii. To a solution suspected of Lead salt add Potassium Iodide solution


Golden yellow precipitates formed with Potassium iodide

solution.

Confirm Pb2+ Present

iv. To a solution suspected of Lead salt add Ammonium sulfide solution.


Black precipitates formed with Ammonium sulfide solution Confirm Pb2+Present

c. CALCIUM

To a solution suspected of Calcium salt add Ammonium Hydroxide solution,

then add little Ammonium Oxalate solution then add Acetic acid


White precipitates formed with Ammonium hydroxide and

Ammonium Oxalate and insoluble in acetic acid.

Confirm Ca2+ Present

d. ZINC

i. To a solution suspected of Zinc salt add Ammonium sulfide solution.


White precipitates formed with Ammonium sulfide solution Confirm Zn2+ Present

ii. To a solution suspected of Zinc salt add Potassium Ferro cyanide

solution


White precipitates formed with Potassium Ferro cyanide

solution.

Confirm Zn2+ Present

e. FERROUS

i. To a solution suspected of Iron (ii) salt add little Potassium Ferric

cyanide solution


Dark blue precipitates formed with Potassium ferric cyanide

solution

Confirm Fe2+ Present

ii. To a solution suspected of Iron (ii) salt add a little Potassium

Thiocyanate solution


No reaction (Trace of red film) with Potassium thiocyanate

solution.




iii. To a solution suspected of Iron (ii) salt, add a little Sodium Hydroxide

solution.


Green precipitates turned on the surface with NaOH solution Confirm Fe2+ Present

f. FERRIC

i. To a solution suspected of Iron (iii) salt, add Potassium Ferric cyanide

solution.


Dark solution no precipitates formed with Potassium ferric

cyanide solution.


ii. To a solution suspected of Iron (iii) salt, add Potassium Thioyanate

solution.


Deep red solution formed with Potassium thiocyanate solution. Confirm Fe3+ Present

g. AMMONIUM

i. To a solution suspected of Ammonium salt. Add few drops of nesslers

reagent.


Brown precipitates formed with few drops of Nessler’s reagent Confirm NH4+ Present

ii. To a solution suspected of Ammonium salt, add Sodium hydroxide

solution and warm the mixture.


Colorless gas evolved with pungent smell on adding NaOH

solution. The gas forms white dense fumes with Hydrogen

Chloride gas. The gas turned red litmus paper to blue.

Confirm NH4+ Present

FLAME TEST Clean a nichrom wire by alternatively heating and quenching in fresh concentrated

HCl in a watch glass, until no color is imparted to the flame.

Dip the wire into concentrated HCl and pick up a trace of the salt on the tip and place

the wire luminous flame. Note the color imported.


Golden yellow flame Confirm Na+ present

Lilac flame Confirm K+ present

Green flame Confirm Cu2+ present

Brick red flame Confirm Ca2+ present

Blue grey flame Confirm Pb2+ present



Example showing how to carry out a systematic qualitative analysis from a give sample

of salt.

The analysis will base on salt S.


Appearance of the salt S. Blue crystals with no smell. Suggest Cu2+ of SO42+ or

NO3-

Solubility of the salt S in

water.

Salt S soluble in cold water

and form clear solution.

Suggest Cl-, NO3-,SO3

2-

,HCO3-, or certain SO4

2-

Action of heat on salt S. Water vapor was given off.

The salt changed from blue

to white after heating.

Suggest hydrated salt of

CuSO4 Present.

Salt S with dilute

Hydrochloric acid.

No gas evolved on cold and

warmed dilute HCl but the

salt S dissolved and gave

clean solution. The solution

form white precipitates with

Barium Chloride solution.

Suggest SO42- Present.

Salt S with concentration

sulfuric acid.

No gas evolved in cold and

warmed conc. Sulfuric acid

but the salt changed its

color to white.

Suggest SO42- present.

CONFIMATORY TEST FOR ANIONS


Salt S solution with Barium

chloride solution.

White precipitates formed

insoluble in excess dilute

Hydrochloric acid.

Confirm SO42- present.

Salt S with Sodium

Hydroxide solution.

Pale Blue precipitates

insoluble in excess alkalis.

Confirm Cu2+ present.

Salt S solution with

Ammonium Hydroxide

solution.

Pale blue precipitates

soluble in excess

Ammonium Hydroxide to

form deep blue solution.

Confirm Cu2+ present.

CONFIMATORY TEST FOR CATIONS:


Salt S solution with

Potassium ferrocyanide

solution.

Brown precipitates formed. Confirm Cu2+ present.



10. CONCLUTION

The cat ion in salt S is Cu2+

The anion in salt S is SO42-

The salt S is CuSO4.

Reviewed by

Ali Suleiman Ali (alsal)

26/04/2016 at 21:42:33 AM.

qualitative analysis sheet for o level chemistry

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