FIRST YEAR PUC
PRACTICALS SYLLABUS
Basic Laboratory Techniques
1.
2.
3.
4.
cutting glass tube and glass rod
Bending a glass tube
Drawing out a glass jet
Boring a cork
Characterization and purification
of chemical substances
1. Determination of melting point of an
organic compound
2. Determination of boiling point of an
organic compound
3. crystallization of impure sample of
anyone of the following:
Alum, Copper sulphate,
sulphate, Benzoic acid.
Experiments related to pH change
• Any one of the following experiments:
•
* Determination of pH of some solution
obtained from Fruit juice, varied concentration
of acid, base and salts using pH paper or
universal indicator.
* Comparing the pH of solution of strong and
weak acid of same concentration
* Study the pH change in the titration of a
strong base using universal indicator.
Study the pH change by common ion effect in
case of weak acid and weak base.
Chemical equilibrium
• Study the shift in equilibrium
between ferric ions and thiocyanate
ion by increasing/ decreasing the
concentration of either ions.
• Study the shift in equilibrium
between [Co(H2O)6]2+ and chloride
ions by changing the concentration
of either of the ions.
Quantitative estimation:
• Using a chemical balance.
• Preparation of standard solution of oxalic
•
•
•
acid.
Determination of strength of a given
solution of NaOH by
titrating it against
standard solution of oxalic acid.
Preparation of standard solution of sodium
carbonate.
Determination of strength of a given
solution of HCl by titrating it against
standard Na2CO3 solution.
Qualitative analysis of inorganic salt
Determination of anion and cat ion in a
given salt.
Anions:-Anions:
CO33-, S-2, SO33-, SO44-, NO3-, Cl-, Br-,
I-, PO43-, C2O42-, CH3COO-.
Cat ions:ions:Pb2+, Cu2+, As3+, Al3+, Fe3+, Mn2+, Ni2+,
Zn2+, Ca2+, Sr2+, Ba2+.
• Detection of nitrogen, sulphur,
sulphur, chlorine.
Common apparatus use
in Laboratory
and their uses
Conical flask
Burette
Measuring cylinder/ volumetric flask
Burette
Lower meniscus of solution in burette
Beaker
Test tubes and test stand
Separating funnel
Bunsen burner
Bunsen Flame
Round bottom flask
Tripod stand
Crucible tongs
Graduated/ measuring cylinders
Droppers
Test tube holders
Measuring cylinders
Watch Glass
Volumetric Measuring flask
Funnel
Reagent bottles
Wash bottle ( water bottle)
Wire gauze
Chemical Balance
Thiele’s Tube
Spatulla
Kipp’s apparatus
TEST TUBE BRUSH
Preparation of
Standard Solution of Sodium Carbonate
QUALITATIV ANALYSIS OF
INORGANIC SALT
Preliminary Examination of Salt.
Colour
Soluility
ANALYSIS OF ACIDIC RADICALS
Preliminary test with dilute Sulphuric Acid
Test
0.1g of
Salt +dil
H2SO4
warm
Observation
1)A colourless ,
Odourless gas
of CO2 is
evolved with
brisk
effervescence,
which turns lime
water milky
Inference
Carbonate
(CO32-) is
present
2)Colourless gas of
H2S with smell of
rotten egg is
evolved which turns
lead acetate paper
black
3)Colourless gas SO2 with
a pungent smell which
turns acidified K 2Cr2O7
Solution green
Sulphide
(S2-) is
present
Sulphite
(SO32-) is
present
4)Brown gas which
turns acidified KI
solution containing
starch solution blue
5)Colourless vapour
with smell of
vinegar, vapour
turns blue litmus
red
Nitrite
(NO2-) is
present
Acetate
(CH3COO-)
is present
Confirmatory test for CO32- S2- SO32- NO3and CH3COOA)
0.1g of salt + dilute H4SO4
Carbonate CO2 gas evolved with
ion (CO32-) bricsk effervescence
which turn s lime water
milky.
D) Nitrite ion. 1 mL of water extract + few
(NO3-)
drop of KI solution and add
few drop of starch solution
acidify with acetic acid. Blue
colour appears.
B) Sulphide 1mL of water extract +
ion (S2-)
ammonium hydroxide add
a drop of sodium
nitroprusside solution.
Purple or violet
colouration appears.
C) Sulphite
ion (SO32-)
1 mL of ate extract + BaCl2
solution. A white ppt is
formed which dissolves in dil.
HCl.
E) Acetate
ion
(CH3COO-)
0.1g of salt in a china dish
add 1mL of ethanol and
0.2mL conc. Sulphuric acid
and heat, Fruity odour
evolved.
If no positive result obtained in step I then go
for Step II
Step II: Preliminary test with conc Sulphuric acid:
Test
0.1 g of
salt + 3-4
drop of
Conc.
Sulphuric
acid and
Warm
Observation
1) Colourless gas with
pungent which gives
dense white fumes
when a rod dipped in
NH4OH is brought near
mouth of the test tube.
2) Reddish brown gas
with pungent smell
heating. After adding of
solid MnO2, solution
acquires red colour
Inference
Chlorid ion
(Cl-) is
present
Bromide
ion(Br-) is
Present
3) Violet vapour which Iodide ion(I-)
turns starch Paper blue is Present
and a layer of violet
sublimate is formed on
side of test tube
fumes become dense
on adding MnO2.
4) Brown fumes evolved Nitrite ion
which become dense by (NO -) is
3
heating with cu- turning
Present
and solution turn blue
colour.
5) Colourless gas,
Oxalate ion
odourless gas evolved (C2O42-) is
which turns lime
Present
water milky an gas
coming out of lime
water burns with
a blue flame if ignite.
Confirmatory test for Cl-,Br-, I-, NO3-, and
c2O42-. Radicals
A) Chloride
ion.(Cl-)
a) 0.1g of salt + pich of MnO2
and 3-4 drop conc. H2SO4 heat
the mixture
Greenish yellow chlorine gas is
evolved which gives pungent
odour.
b) 1mL of sodium carbonate
extract acidify with dil. HNO3 or
take water extract and add
silver nitrate solution . A curdy
white ppt. is obtained which
soluble in NH4OH solution
B) Bromide a) 0.1 g of salt + pinch of
ion. (Br-)
MnO2 add 3-4 drop conc.
H2SO4 heat the mixture .
Intense brown fumes
evolved.
b) 1mL of sodium extract
acidified with dil. HNO3 or
take water extract and add
silver nitrate solution. A
pale yellow ppt which is
slowly soluble in NH4OH
solution.
C) Iodide a) 1 mL of salt solution
Ion. (I-)
neutrilization with Hcl & add
1 mL CHCl3 or CCl4, now add
an excess of chlorine water
drop by drop and shake TT. A
violet colour appears in the
organic layer.
b) 1 mL of sodium carbonate
extract acidify with dil HNO3
or takes water extract, add
AgNo3 solution A yellow ppt
in soluble in NH4OH solution
is obtained.
D) Nitrate 1 mL Water extract add 2 mL
Ion (NO3-) conc. H2SO4 mix through cool
the mixture under the tap.
Add freshly prepared FeSO4
solution along the side of TT
without shaking A dark
brown ring is formed at the
junction of the two solution.
E) Oxalate 1 mL of water extract
ion (C2O42- acidified with acetic acid
)
and add calcium chloride
solution. A white ppt
insoluble in ammonium
oxalate and oxalic acid but
soluble in dil Hcl & dil
HNO3.
if no positive test is obtained in step I & II
then go for step III
III Test for SO42- and PO43Confirmatory test for Sulphate & Phosphate ion
•
Sulphate
(SO4-2)
1 mL water extract + dil
HCl +Bacl2 solution white
ppt insoluble in conc. HCl is
obtained.
Phosphate 1 mL water extract + conc.
Ion (PO4-3) HNO3 and add ammonium
molubidate solution & boil
A canary yellow ppt is
formed.
SYSTEMATIC QUALITATIVE
ANALYSIS OF INORGANIC SALT
Preliminary examination of the salt for cation
Observation
Inference
Test
Colour
Light green, yellow, brown
Blue
Bright green
Blue, red, Violet, pink
Light pink
Fe2+,Fe3+
Cu2+
Ni2+
Co2+
Mn2+
• Dry heating test:
0.1g of salt is heated in dry test tube and observe
the colour of salt in hot and also when it become
cold.
Colour when cold
Blue
Cu2+
Green
White
Pink
Colour when hot
White
Inference
Dirty white or yellow
yellow
Blue
Fe2+
Zn2+
Co2+
• Flame test:
Platinum loop is dip in the paste of salt and held in the
non--luminous flame. Observe the colour of flame first
non
with nicked eye and then through a blue glass.
•
Color of flame observed by
Inference
Naked eye
•
•
•
•
Colour of flame observed by
through blue glass
Green flame with blue center no change
Crimson red
Purple
Apple green
Bluish green
Brick red
Green
Cu2+
Sr2+
Ba2+
Ca2+
Preparation of Original
solution(O.S.)
Salt is dissolved in distilled water if not
soluble then heat, if even insoluble then
salt dissolved in dil. HCl or Conc. HCl or
dil. HNO3 or a mixture of conc. HCl and
COnc. HNO3 in the ratio of 3:1 this
mixture is called Aqua regia.
regia. A salt not
soluble in aqua regia is considered to be
an insoluble salt.
Analysis of Zero group cat ion (NH4+
ion)
• 0.1 g of a salt and add 11-2mL of NaOH solution and heat
If there is a smell of ammonia this indicate the presence
of ammonium ions. Ring the glass rod dipped in HCl near
the mouth of the test tube. White fumes are observed.
observed.
• Pass the gas through Nessler’s reagent. Brown ppt. is
obtained
ANALYSIS OF BASIC RADICALS
Test
observation
Inference
• O.S. + dil. HCl
White ppt
No ppt
I-group Pb2+ is present
IIII-group is absent
• O.S. + dil. HCl + pass H2S gas.
Black PPt.
Yellowppt
No ppt.
IIII-group Cu2+, Pb2+
As3+ is present
IIII-group is absent
• O.S. + Solid NH4Cl
Brown ppt.
IIIIII-group Fe3+
White gelatinous ppt.
Al3+ is present
No ppt.
IIIIII-group is absent
+ excess NH4OH
Test
• O.S
O.S.. +solid NH4Cl
+ excessNH4OH
+passH2S.
• o.s
o.s.. + solid NH4Cl
Ba2+,Ca2+,Sr2+
observation
Inference
White PPt.
PPt.
Flesh colour ppt
IV
IV--group Zn2+
Mn2+
Black ppt.
Ni2+, Co2+is presnt
No ppt.
IV- group is absent
White ppt.
V-group
+ excess NH4OH
+ solid (NH4)2CO3
is present
No ppt.
VI
VI-- group Mg2+ is
present
Analysis of Group I cation:
cation:
(Pb2+)
• Dissolve the ppt in hot water and divide
into two parts.
Part 1 + KI solution
Part 2 + potassium chromate
confirmed
solution
yellow ppt
Pb2+ is confirmed
Yellow ppt which is
Pb2+ is
soluble In NaOH solution
Analysis of Group II cation:
cation: (Pb2+, Cu2+ ,
As3+ )
•
II group PPt + yellow ammonium
Sulphide solution and shake
•
Confirmatory test for Pb2+ and Cu2+ ions
•
II group ppt boil with
dil HNO3and add few drop of
alcohol and dil. H2-SO4 .
•
This White ppt is dissolved in
ammoniumAcetate + acetic acid+ KI
Solution
•
If no white ppt add excess of
NH4OH solution + acetic acid
+ potassium ferro cyanide solution.
PPt is insoluble
PPt is soluble
White ppt.
Pb2+, Cu2+ is present
As3+ is present
Pb2+ is confirmed
yellow ppt
Pb2+is confirmed
Chocolate brown ppt
Cu2+ is confirmed
Analysis of Group III cations:
cations:
(Fe3+, Al3+)
• Brown ppt dissolve in dil HCl and divide the solution into two part.
• Part I + potassium
Blue ppt. or
Fe3+ is confirmed
ferrocyanide Solution
• Part 2+ potassium thiocyanate
colour appears
Blood red
Fe3+ is confirmed.
coloration appears
• White gelatinous ppt dissolve
• in dil. HCl + NaOH solution
White gelatinous
Al3+ is confirmed.
ppt soluble in excess
Analysis of Group IV cations:
cations: (Zn2+, Mn2+,Ni2+, and
Co2+)
•
Dissolve the white ppt in
dil. HCl and boil
+ NaOH solution.
White PPt soluble
in excess
•
Dissolved the flesh ppt in
dil. HCl and boil
+ excess NaOH solution.
White ppt
which turns brown
•
Dissolve the black ppt in aqua regia heat the solution to dryness and cool. Dissolve the residue in water and
divide the solution into two Parts.
•
To first part + NH4OH more +
few drop of dimethyl glyoxime
(DMG)shake
To second part+ NH4OH +
actic acid+ solid KNO2.
•
Zn2+ is confirmed.
Mn2+ is confirmed.
Bright red ppt
Ni2+is confirmed.
Yellow ppt
Co2+ is confirmed.
Analysis of Group V cations:
cations: (Ba2+, Sr2+
and Ca2+)
•
•
•
Dissolve the ppt by boiling with dil. Acetic acid and divide the solution into three parts.
First part + potassium
Chromatesolution
yellow ppt
Ba2+is confirmed.
FLAME TEST
Paste of salt in conc. HCl is held
on the Bunsen flame
grassy green flame
Ba2+ is confirmed.
White ppt
Sr2+ is confirmed
•
second part + (NH4)2SO4 solution
Heat and scratch the side of the
Tes t tube with glass rod.
•
•
FLAME TEST
Paste of salt in conc. HCl is held
on the Bunsen flame
Crimson red flame
Sr2+ is confirmed.
Third part + ammonium oxalate
Solution shake well
White ppt
Ca2+ is present.
FLAME TEST
Paste of salt in conc. HCl is held
on the Bunsen flame
Brick red flame
Ca2+ is confirmed.
•
•
•
Analysis of Group VI cation
+2
(Mg )
• If Group V is absent then perform the test
for Mg+2+ ions.
• OS+NH4OH
White ppt
+Na2HPO4 Solution
confirmed
Mg+2 is
Titrimetric analysis
Aim:- Preparation of 250 mL of 0.1M Standard
Aim:solution of Oxalic acid.
• Theory:
• Hydrated oxalic acid is dibasic weak acid and its molar mass is 126 g. If
126g of oxalic acid is present in one liter of the solution It is known as one
molar (1.0M) solution. There for preparing 250mL of 0.1M oxalic acid
solution, we required: 126g x 0.1M x 250mL/ 1000mL =3.1500g of
hydrated oxalic acid.
•
In general for preparing a solution of required molarity,
molarity, the amount of
substance to be weighed can be calculated by using the formula given
below:
Molarity (M) =
-----
Mass of solute in grams(m) x 1000
-------------------------------------------------------------------------------Molar mass of solute x vol. of solution to be prepared in mL
mL(v)
(v)
Procedure:
• Weigh an empty watch glass accurately. Then
weigh 3.1500g oxalic acid on the above watch
glass. Transfer oxalic acid carefully from the
watch glass into a clean measuring flask using
a funnel. Weigh the empty watch glass again
and find out the mass of oxalic acid
transferred to the measuring flask. Wash
funnel several times with distilled water by
using a wash bottle to transfer the sticking
particles. Swirl the measuring flask till solid
oxalic acid is completely dissolved Add more
distilled water to make up the volume with
distilled water up to the mark by adding last
few mL drop wise. Stopper the flask and shake
it thoroughly to make the solution
Aim:- Determination of the concentration( strength) of a
Aim:given sodium hydroxide solution by tritrating it against a
standard solution of oxalic acid.
• Reaction:
COOH
COOH
+ 2NaOH ---
---
COONa
COONa + 2H2O.
• Procedure:
Wash the burette with distilled water and rinse the burette with sodium
hydroxide solution. Then fill sodium hydroxide solution into the burette through a
funnel above the zero mark.
Remove the air gap, if any from the nozzle of the burette and remove the
funnel Note the initial reading by keeping the eye exactly at the same level as the
lower meniscus of the solution.
Pipette out 10mL of oxalic acid solution in a clean conical flask. Add 11-2 drops
of phenolphthalein indicator to the conical flask. Titrate the acid with sodium
hydroxide solution till a very faint permanent pink colour is obtained. Read the lower
meniscus of the solution in the burette and note down.
Repeat the procedure until three concordant readings are obtained.
•
Table
•
•
Calcuation:
Molarity of NaOH solution can be calculated by using the equation:
Oxalic aid
Sodium hydroxide
=
a2M2V2
a1M1V1
Where, M1 and V1 are the molarity and volume of the oxalic acid, a1 is basicity of oxalic
acid =2
M2 and V2 are the molarity and volume of the sodium hydroxide solutio0n ,a2 is
acidity of sodium hydroxide solution =1
Calculate the concentrqatiuon of sodium hydroxide solution in g/L.
Concentration (strength) in g/L = Molartity x Molar mass.
Result:
The concentration of the given NaOH solution is ________ g/L
Aim:- preparation of 0.1M slandered
Aim:solution of sodium carbonate.
• Theory:
• Molar mass of dry sodium carbonate is 106g. To prepare
0.1M Na2CO3 solution, 10.6000g of sodium carbonate
should be dissolved per liter of the solution.
• There fore to prepare 100 mL of 0.1M Na2CO3 solution
1.0600g of sodium carbonate is dissolved in minimum
quantity of water and the solution id diluted exactly
100 mL by adding water.
Procedure:
• Weigh an empty watch glass accurately. Then weigh
1.0600g Sodium carbonate on the above watch glass.
Transfer Sodium carbonate carefully from the watch
glass into a clean measuring flask using a funnel. Weigh
the empty watch glass again and find out the mass of
Sodium carbonate transferred to the measuring flask.
Wash funnel several times with distilled water by using a
wash bottle to transfer the sticking particles. Swirl the
measuring flask till solid Sodium carbonate is completely
dissolved Add more distilled water to make up the
volume with distilled water up to the mark by adding last
few mL drop wise. Stopper the flask and shake it
thoroughly to make the solution.
Aim:- Determination of the strength of a given solution of
Aim:dilute hydrochloric acid by titrating it against a standard
solution of sodium carbonate.
• Reaction:
Na2 CO3 + 2HCl - 2 NaCl + H2O + CO2
• Procedure:
Wash the burette with distilled water and rinse the burette with
hydrochloric acid solution. Then fill hydrochloric acid solution into the
burette through a funnel above the zero mark.
Remove the air gap, if any from the nozzle of the burette and remove
the funnel Note the initial reading by keeping the eye exactly at the same
level as the lower meniscus of the solution.
Pipette out 10mL of Sodium carbonate solution in a clean conical
flask. Add 11-2 drops of Methyl orange indicator to the conical flask. Titrate
the Base with hydrochloric acid solution till Colour changes from yellow to
pinkish--red colour is obtained. Read the lower meniscus of the solution in
pinkish
the burette and note down.
Repeat the procedure until three concordant readings are obtained.
•
Table
•
•
Calculation:
Molarity of HCl solution can be calculated by using the equation:
HCl solution
a1 M1 V1 =
Where,
•
Na2CO3 solution
a2 M2 V2
M1 and V1 are the molarity and volume of the HCl solution, a1 is basicity of HCl = 1
M2 and V2 are the molarity and volume of the sodium carbonate solution ,a2 is acidity
Of sodium carbonate solution = 2
Calculate the concentration of hydrochloric acid solution in g/L.
Molar mass of hydrochloric acid is 35.5 g mol-1
Concentration (strength) of HCl solution in g/L = Molartity x Molar mass.
Result:
The concentration of the given HCl solution is ________ g/L