CHEMISTRY PRACTICALS FOR CLASS XII TERM II EXAMINATION

Instructions:
 Write all these (08) experiments in individual ruling pages only.
 Don’t do any diagrams.
 You must write your name, board roll no, school name, year etc.
definitely.
 Please fill up your content page.
 Along with these experiments written in a practical record copy, all
students have to submit a project.
 The topic is available in the CBSE website.
 Choose any one.
EXPERIMENT-01
AIM OF THE EXPERIMENT: To prepare crystals of ferrous ammonium sulphate (Mohr’s salt)
Theory:
When a solution containing equimolar proportions of FeSO4 and (NH4)2SO4is crystallized,
crystals of double salt i. e Mohr’s salt separate out.
Equation involved:
FeSO4 + (NH4)2SO4 + 6H2O  FeSO4. (NH4)2SO4.6H2O
Chemicals required:
Ferrous sulphate
Ammonium sulphate
Dil Sulphuric acid
Distilled water
Materials required:
250 ml beaker
Glass rod
Tripod stand
Funnel
Bunsen burner
Wire gauge
Watch glass
Filter paper
China dish
Pastle and mortar
Procedure:
1. Approximately 13g of FeSO4 (0.05 mole) and 6.6g of (NH4)2SO4(0.05 mole) are
weighed separately.
2. They are dissolved separately (after powdering by Pastle and mortar) in 20 ml of
distilled water containing 1 to 2 ml of dilute H2SO4 in a beaker.
3. The solution is stirred well.
4. The solution is filtered with the help of funnel so as to remove suspended impurities.
5. The above solution is heated in a China dish till crystallization point is reached.
6. There after the solution is left undisturbed for slow cooling.
7. After one hour, crystals of ferrous ammonium sulphate will be observed.
8. Now the crystals are separated by decantation.
 9. Then crystals are placed in between the folds of the filter paper and dried.
10. Now the colour and shape of the crystals are observed.
11. Lastly the dried crystals are weighed, noted and submitted for inspection.

Observation:

Colour of the crystal: - _______pale green

Shape of the crystal: -________monoclinic
Yield of the crystal: -_________17.8g

Precautions:

1. The solution should not be allowed to cool rapidly.

2. During crystallization, solution should not be disturbed and should be covered with a watch
glass.
3. Heating should be done for a short time only as long heating may cause the formation of
Fe3+ ions.
4. Dry crystals should be kept in an air tight container rather it will get oxidized.
5. If the solution becomes yellow in colour, it should be thrown and processed again.

EXPERIMENT- 02
AIM OF THE EXPERIMENT: To prepare crystals of potash alum.
Theory:
When a solution containing equimolar proportions of K2SO4 and Al2(SO4)3is crystallized,
crystals of double salt i. e Mohr’s salt separate out.
Equation involved: K2SO4 + Al2(SO4)3 + 24H2O  K2SO4. Al2(SO4)3.24H2O
Chemicals required:
Potassium sulphate
Aluminum sulphate
Dil Sulphuric acid
Distilled water
Materials required:
250 ml beaker
Glass rod
Tripod stand
Funnel
Bunsen burner
Wire gauge
Watch glass
Filter paper
China dish
Pastle and mortar
Procedure:
1. Approximately 33g of Al2(SO4)3 (0.07 mole) and 12g of K2SO4 (0.07 mole) are weighed
separately.
2. Al2(SO4)3 are (after powdering by Pastle and mortar) dissolved in 50 ml of Luke warm
distilled water (temp-300 – 400) containing 1 to 2 ml of dilute H2SO4 in a beaker.
3. K2SO4 (after powdering by Pastle and mortar) dissolved in 10 ml of distilled water in
another beaker and added to above.
4. The solution is stirred well.
5. The solution is filtered with the help of funnel so as to remove suspended impurities.
6. The above solution is heated in a China dish till crystallization point is reached.
 7. There after the solution is left undisturbed for slow cooling.
8. After one hour, crystals of ferrous ammonium sulphate will be observed.
9. Now the crystals are separated by decantation.
10. Then crystals are placed in between the folds of the filter paper and dried.
11. Now the colour and shape of the crystals are observed.
12. Lastly the dried crystals are weighed, noted and submitted for inspection.

Observation:

Colour of the crystal: - _______colorless

Shape of the crystal: -________octahedral
Yield of the crystal: -_________40.5g

Precautions:

1. The solution should not be allowed to cool rapidly.

2. For dissolving warm water should be used.
3. During crystallization, solution should not be disturbed and should be covered with a watch
glass.
4. Heating should be done for a short time only.
5. Dry crystals should be kept in an air tight container rather it will get oxidized.

EXPERIMENT-03
AIM OF THE EXPERIMENT: To find out the cationic (basic radical) part and (anionic) acid radical part
of the supplied sample of salt(X1)

Salt no: _X1__

Experiment Observation inference

Physical examination
 Colour white Cu2+, Fe3+, Ni2+, Mn2+, Co2+ may be
 Smell No specific smell absent
NH4+, S2-, CH3COO- may be absent
NO3-, SO3- may be present
Crystalline solid
 Physical state
Dry test tube heating
A pinch of salt taken in a clean and
dry test tube and heated strongly.
 If any Gas evolved
A colorless odourless gas CO32-may be present.
evolved which turns lime
 If sublimation takes place water milky
 Decrepitation takes place No sublimation Ammonium halides, iodides may
 Fusion occurs be absent.
 Colour residue is formed No cracking sound observed. Pb2+, Ba2+, NO3-, I-, Cl-may be
present
Yellow when hot and cold

Charcoal cavity test

Pinch of salt + double the amount Yellow when hot and cold May be crystalline salts of Pb and
of Na2CO3 then heated the mixture leads to charcoal reduction test.
in charcoal cavity in reducing flame
Charcoal reduction test White shining malleable bead Pb2+ may be present
A mixture of salt and charcoal is formed with yellow
powder and fusion mixture in the incrustation and the bead
proportion 1:3:1 is prepared. A marks the paper
little of the mixture is taken in a
charcoal cavity and heated in a
reducing flame with a blow pipe.
Borax bead test
The test is not performed as the
salt in above test is white
Test for acid radicals:

Dil H2SO4 test

Pinch of salt + 1-2 ml of Dil H2SO4 A colorless odourless gas CO32- may be present.
evolved with brisk
effervescence which also turns
lime water milky

KMnO4 test
Pinch of salt + 1-2 ml of Dil H2SO4 Pink colour of KMnO4 did not Cl-, Br-, I- may be absent
then heated and few drops of get discharged.
KMnO4 is added.
Conc. H2SO4 test
Pinch of salt + 1-2 ml of Dil H2SO4 No gas evolved Cl-, Br-, I- NO3- may be absent
and heated
Confirmatory test for anion
Pinch of salt + water shaken well Did not dissolve Insoluble carbonate indicated
Above + dil HCl
A colorless odourless gas CO32- is confirmed.
evolved with brisk
effervescence which also turns
lime water milky

Wet test for basic radicals:

Preparing OS
Salt is shaken with distilled
water
About 2 c.c. of salt solution was white ppt formed Group I radicals are present.
taken and little dilute HCl was
added to it
.
Confirmatory Test for gr I
Filtered the above ppt, washed
with distilled water then added
with dil HCl and boiled off H2S gas
completely and divided into two
parts

.
Part 1 is added with distilled water The ppt dissolves on heating Pb++ may be present
and boiled. reappears on cooling

Part 2 is added with dil ammonium No change in white ppt Ag+ and Hg2++ are absent
hydroxide and shaken.
Confirmatory test for lead(Pb++)
About 2 c.c. of the supplied salt Yellow ppt of lead iodide was Pb++ is confirmed.
solution was taken and few drops of formed which dissolves on
KI was added. heating and reappears as shining
yellow pallets.
 Hence the basic part of the supplied salt is found to be Pb++.

Conclusion:
Hence the cation is Pb++. and anion is CO32-. And salt will be PbCO3.

EXPERIMENT- 04
AIM OF THE EXPERIMENT: To find out the cationic (basic radical) part and (anionic) acid radical part
of the supplied sample of salt(X1).

Salt no: _(X2)

Experiment Observation inference

Physical examination
 Colour Blue Cu2+ may be present
 Smell No specific smell NH4+, S2-, CH3COO- may be
absent
 Physical state Crystalline solid NO3-, SO3- may be present
Dry test tube heating
A pinch of salt taken in a clean
and dry test tube and heated
strongly.
 If any Gas evolved No gas evolved CO32-, NO3-, S2-, Cl-, NH4+, S2-,
CH3COO-, NO2-, Br-, I- may be
absent.
 If sublimation takes Water vapours get condensed. May be hydrated salts.
place
 Decrepitation takes No cracking sound observed. Pb2+, Ba2+, NO3-, I-, Cl- may be
place absent
 Fusion occurs Salt fused May be hydrated salts.
 Colour residue is white Cu2+ may be present
formed
Charcoal cavity test
Pinch of salt + double the Red beads or scales were Cu2+ may be present
amount of Na2CO3 then heated observed.
the mixture in charcoal cavity
in reducing flame
Cobalt nitrate test
The test is not performed as
the residue in above test was
not white
Borax bead test Green when hot and light blue Cu2+ may be present
Prepared a transparent borax when cold in oxidizing flame
with the help of conc. HCl and Colourless when hot and
performed the test in oxidizing opaque red when cold in
and reducing flame separately reducing flame
Flame test Green coloured flame with Cu2+ may be present
Paste of salt + conc. HCl and blue top
shown to the flame taking on
the tip of a platinum wire
Dil H2SO4 test
Pinch of salt + 1-2 ml of Dil No gas evolved CO32-, SO32-, S2-, Cl-, NO2- may
H2SO4 be absent.
KMnO4 test
Pinch of salt + 1-2 ml of Dil Pink colour of KMnO4 did not Cl-, Br-, I- may be absent
H2SO4 then heated and few get discharged.
drops of KMnO4 is added.
Conc. H2SO4 test
Pinch of salt + 1-2 ml of Dil No gas evolved Cl-, Br-, I- NO3- may be absent
H2SO4 and heated
Preparing OS
Salt is shaken with distilled Blue colour clear solution CO32-may be absent.
water obtained
Test for SO42- ions
 Os + conc HCl + BaCl2 White ppt formed  SO42- confirmed
solution
 Os + acetic acid + lead White ppt formed which  SO42- confirmed
acetate solution + dissolves in excess of
ammonium acetate in ammonium acetate.
excess
Caustic soda test
Pinch of salt + NaOH + and No white fumes and no smell NH4+ absent
heated. Brought a glass rod of ammonia.
dipped in conc HCl near the
mouth of the test tube
Os + dil HCl No white ppt Gr I absent
Os + dil HCl + H2S gas passed Black ppt formed Gr II present
Test for gr II
Filtered the above ppt, washed
with distilled water then
added with 50% HNO3 and
boiled off H2S gas completely
and divided into two parts
 Part a cooled then
added with NH4OH in Deep blue coloured solution Cu2+ is confirmed
excess was formed
 Part b + acetic acid +
potassium Chocolate brown ppt formed Cu2+ is confirmed.
ferrocyanide solution

Conclusion:

Hence the cation is Cu2+ and anion is SO42-. And salt will be CuSO4.

EXPERIMENT= 05
AIM OF THE EXPERIMENT: To find out the cationic (basic radical) part and (anionic) acid radical part
of the supplied sample of salt(X1)

Salt no: _(X2)

Experiment Observation inference

Physical examination
 Colour White Cu2+ may be present
 Smell Salt is rubbed in palms and  may be the salt is
smelled and found ammonia ammonium salt.
like smell
 Physical state Crystalline solid NO3-, SO3-, SO42-may be
present
Dry test for basic radicals:
experiment observation inference
Dry test tube heating
 A pinch of salt was A sublime is formed and the May be NH4+,As3+or Hg2+
taken in a clean and salt was found to be
dry test tube and completely volatile.
heated strongly

Soda lime test

A pinch of salt was taken on a Ammonia gas is evolved and May be NH4+
watch glass and a little soda the colour of the mixture is
lime with a drop of water is not changed
added to it.
Test for acid radical
Dil H2SO4 test
Pinch of salt + 1-2 ml of Dil No gas evolved CO32-, SO32-, S2-, Cl-, NO2- may
H2SO4 be absent.
KMnO4 test
Pinch of salt + 1-2 ml of Dil Pink colour of KMnO4 did not Cl-, Br-, I- may be absent
H2SO4 then heated and few get discharged.
drops of KMnO4 is added.
Conc. H2SO4 test
Pinch of salt + 1-2 ml of Dil No gas evolved Cl-, Br-, I- NO3- may be absent
H2SO4 and heated
Preparing OS
Salt is shaken with distilled Blue colour clear solution CO32-may be absent.
water obtained
Test for SO42- ions
 Os + conc HCl + BaCl2 White ppt formed  SO42- confirmed
solution
 Os + acetic acid + lead White ppt formed which  SO42- confirmed
acetate solution + dissolves in excess of
ammonium acetate in ammonium acetate.
excess

Wet test for basic radicals:

experiment observation inference

About 2 c.c. of salt solution was No white ppt formed Group I radicals are absent.
taken and little dilute HCl was
added to it
.
The above solution is warmed a No ppt formed Group II radicals are absent.
little and H2S gas is passed
through it
About 2 c.c. of salt solution was No ppt formed Group IIIA radicals are absent.
taken and little solid NH4Cl was
added till saturation then dilute
NH4OH was added to it till
alkaline.

The above solution is H2S gas is No ppt formed Group IIIB radicals are absent.
passed through it.
About 2 c.c. of salt solution was No white ppt formed Group I V radicals are absent
taken and little solid NH4Cl was and confirms presence of group
added till saturation then dilute V.
NH4OH was added to it till
alkaline. Lastly saturated
solution of ammonium
carbonate is added to it.

Confirmatory test for ammonium(NH4+)

About 2 c.c. of the supplied salt Brown ppt formed NH4+ is confirmed.
solution was taken and few
drops of NaOH was added
followed by Nessler’s reagent

Hence the basic part of the supplied salt is found to be NH4+ and acid part of the supplied
salt is SO42-. And salt will be (NH4)2SO4.

EXPERIMENT-06
AIM OF THE EXPERIMENT: To prepare 250 ml of its solution and determine the percentage
oxidation of the that Mohr’s salt solution.

Theory

Molecular mass of Mohr’s salt- FeSO4(NH4)2SO4. 6H2O = 392 g mol-1.

Hence for preparing 1000 ml of 1M Mohr’s salt solution Mohr’s salt required is 392g

For preparing 250ml of M/20 Mohr’s salt solution, Mohr’s salt required = x250 x = 4.9g.

Procedure for the preparation of the solution:

1. Weighed the clean and dry watch glass and recorded its weight in the note book.
2. Weighed accurately 4.9g of Mohr’s salt crystals on the watch glass and recorded the wight in
the note book.
3. Transferred carefully the weighed Mohr’s salt from the watch glass into a clean 250ml
beaker.
4. Added to this beaker about 5 ml of conc. Sulphuric acid to check the hydrolysis of ferrous
sulphate.
5. Washed the watch glass thoroughly with distilled water to transfer the sticking salt
completely into the beaker.
6. Dissolved the salt in the beaker with gentle stirring.
7. Transferred the entire solution carefully into the 250ml measuring flask through a funnel.
8. Washed the beaker with distilled water and transfer the washings into the measuring flask.
9. Added enough distilled water to the measuring flask carefully up to just below the etched
mark on its neck with the help of a wash bottle.
10. Added last few drops of distilled water with a pipette until the lower level of the meniscus
just touches the mark on the measuring flask.
11. Stoppered the measuring flask and shake it gently to make the solution homogeneous and
labelled it as M/20 Mohr’s salt solution.
Chemical equation involved:

Molecular equation:

2KMnO4 + 3H2SO4 K2SO4 + 2MnSO4 + 3 H2O + 5[O]

{2FeSO4.(NH4)2SO4.6H2O + H2SO4 + [O]Fe2 (SO4)3 + 2(NH4)2SO4 + 13H2O} X 5

2KMnO4 + 8H2SO4 + 10 FeSO4. (NH4)2SO4.6H2O  K2SO4 + 2MnSO4 +5 Fe2 (SO4)3 + 10(NH4)2SO4 +

68H2O

Ionic equation:

MnO4- + 8H+ + 5e- Mn2+ + 4H2O

 [Fe2+ Fe3+ + e-] X 5

MnO4- + 8H+ + Fe2+ Fe3+ + 4H2O

Indicator used:

KMnO4 is a self-indicator.

End point:

Just reaching the pink colour.

Tabulation:

Sl no Volume of Initial burette Final burette Difference in Remarks

Mohr’s salt reading in ml reading in ml ml
taken for
titration in ml
01 10 0.0 5.7 5.7 rough
02 10 5.7 11.3 5.6 concordant
03 10 11.3 16.9 5.6 concordant
04 10 16.9 22.5 5.6 concordant

Calculations:

Molarity of the KMnO4 solution

2 moles of KMnO4 reacts with 10 moles of Mohr’s salt.

Let molarity of KMnO4 = M1

Molarity of Mohr’s salt solution = M2

Volume of KMnO4 = V1

Volume of Mohr’s salt solution = V2

 X =
 X =

 M1 = X =
Strength of the KMnO4 solution

Strength (in g L-1) = molarity x molar mass = x 158 g mol-1 = ∗ .

x 158 g mol-1 =0.0197 x 158 =
3.11g L-1 = a (say)

Here 4.9g of Mohr’s salt is dissolved in 250 ml of water.

 In 1l of water the Mohr’s salt dissolved will be = 4.9 x 4 = 19.6g

( . ) ( . . ) .
 % oxidation = .
x100 = .
x100 = .
x100 = 0.841 x 100 = 84.1

Conclusion:

Hence the percentage oxidation of the that Mohr’s salt solution.

Is found to be 84.1.

EXPERIMENT- 07
AIM OF THE EXPERIMENT: To prepare 250 ml of its solution and determine the percentage oxidation
of the thatoxalic acid.

Theory
Molecular mass of oxalic acid- (COOH)22H2O = 126 g mol-1.

Hence for preparing 1000 ml of 1M oxalic acid solution oxalic acid crystals required is 126g

For preparing 250ml of M/20 oxalic acid solution, oxalic acid crystals required = x250 x =
1.575g ≈ 1.6g

Procedure for the preparation of the solution:

1. Weighed the clean and dry watch glass and recorded its weight in the note book.
2. Weighed accurately 1.6g of oxalic acid crystals on the watch glass and recorded the wight in
the note book.
3. Transferred carefully the weighed oxalic acid from the watch glass into a clean 250ml
beaker.
4. Washed the watch glass thoroughly with distilled water to transfer the sticking salt
completely into the beaker.
5. Dissolved the salt in the beaker with gentle stirring.
6. Transferred the entire solution carefully into the 250ml measuring flask through a funnel.
7. Washed the beaker with distilled water and transfer the washings into the measuring flask.
8. Added enough distilled water to the measuring flask carefully up to just below the etched
mark on its neck with the help of a wash bottle.
9. Added last few drops of distilled water with a pipette until the lower level of the meniscus
just touches the mark on the measuring flask.
10. Stoppered the measuring flask and shake it gently to make the solution homogeneous and
labelled it as M/20 oxalic acid solution.
Chemical equation involved:

Molecular equation:

2KMnO4 + 3H2SO4 K2SO4 + 2MnSO4 + 3 H2O + 5[O]

(COOH)2.2H2O + [O]2CO2 + 3H2O} X 5

2KMnO4 + 3H2SO4 + 5(COOH)2.2H2O K2SO4 + 2MnSO4 +10CO2+ 18H2O

Ionic equation:

[MnO4- + 8H+ + 5e- Mn2+ + 4H2O] X2

[C2O42- 2CO2+ 2e-] X 5

2MnO4- + 16H+ + 5C2O42- Mn2+ + 8H2O + 10CO2

Indicator used:

KMnO4 is a self-indicator.

End point:

Just reaching the pink colour.

Tabulation:

Sl no Volume of Initial burette Final burette Difference in Remarks

oxalic acid reading in ml reading in ml ml
solution taken
for titration in
ml
01 10 0.0 10.5 10.5 rough
02 10 10.5 20.9 10.4 concordant
03 10 20.9 31.3 10.4 concordant
04 10 31.3 41.7 10.4 concordant
Calculations:

Molarity of the KMnO4 solution

2 moles of KMnO4 reacts with 5 moles of oxalic acid solution.

Let molarity of KMnO4 = M1

Molarity of oxalic acid solution = M2

Volume of KMnO4 = V1

Volume of oxalic acid solution = V2

 X =
 X =

 M1 = X =
Strength of the KMnO4 solution

Strength (in g L-1) = molarity x molar mass = ∗ .

x 158 g mol-1 = x 158 g mol-= 0.0192 x 158 = 3.03in
g L-1=a (say)

Here 1.6g of oxalic acid is dissolved in 250 ml of water.

 In 1L of water the oxalic acid dissolved will be = 1.6 x 4 = 6.4g

( . ) ( . . ) .
 % oxidation = .
x100 = .
x100 = .
x100 = 0.5265 x 100 = 52.65

Conclusion:

Hence the percentage oxidation of the thatoxalic acid solution.

Is found to be 52.65.

EXPERIMENT 08
AIM OF THE EXPERIMENT: To detect the functional group of the supplied organic
compound.

experiment observation inference

About 1ml of the compound No decolorization of bromine Unsaturation is absent.
and add bromine water
dropwise
.
1 ml of compound is added Pink colour persists Do
with acetone and potassium
permanganate solution
Few drops of cerric ammonium No red colour formed Alcoholic gr absent
nitrate is added to 1 ml of the
compound

A pinch of the compound is Litmus paper turns red Phenolic gr absent

dropped on moist blue litmus
paper
To small amount of compound No dark colour May be –COOH gr
5 ml ferric chloride solution is
added
To small amount of compound Brisk effervescence formed. May be –COOH gr
5 ml sodium bicarbonate is
added
Confirmatory test for acids
About 2 c.c. of the supplied A fruity smell comes out acids confirmed.
solution was taken, 1 ml of
ethyl alcohol is added and few
drops of Sulphuric acid was
added and warmed
Hence the functional part of the supplied organic compound is found to be acids.

**********----------**********