CHEMISTRY PRACTICAL 2 · PDF file... Dissolve in potassium sulphate (2.0g) and aluminium...
Transcript of CHEMISTRY PRACTICAL 2 · PDF file... Dissolve in potassium sulphate (2.0g) and aluminium...
CY OTI LS LER GE EVI MNU A- NE GR
AP LS UA RKI U
V
VIKAS PRE-UNIVERSITY COLLEGE
CHEMISTRY PRACTICAL 2
www.vikascollege.com
LAB MANUAL
VIKAS PRE-UNIVERSITY COLLEGE
CHEMISTRY PRACTICAL 2
LAB MANUAL
Index
Experiment No - 1 To prepare a standard ferrous ammonium sulphate solution (Mohr's salt solution) and determine the strength of the given potassium permanganate solution. 03
Experiment No - 2To prepare a standard solution of oxalic acid and determine the strength of given potassium permanganate solution. 05
Experiment No - 3 Preparation of pure sample of potash alum 07
Experiment No - 4Preparation of pure sample of Ferrous ammonium sulphate (FAS/Mohr's salt) 08
Experiment No - 5 Systematic semi-micro qualitative analysis of a simple inorganic salt. 09
Experiment No - 6 Test for the functional group present in organic compounds 14
Experiment No - 7Preparation of Acetanilide from aniline 17
Experiment No - 8Preparation of iodoform crystals 18
Experiment No - 9Preparation of Lyophilic and Lyophobic sol 19
Experiment No - 10 To study the role of emulsifying agent in stabilising the emulsions of different oils 20
Experiment No - 11Determination of heat of neutralization of Hydrochloric acid with Sodium hydroxide 21
www.vikascollege.com
Aim: To prepare a standard ferrous ammonium su lphate solution (Mohr’s salt solution) and
determine the strength of the given potassium permanganate solution.
Principle: Potassium permanganate is a powerful oxidising agent. It oxidizes ferrous sulphate
to ferric sulphate in the presence of dil.H2SO4.
Reactions:
Reduction half reaction: 2KMnO4 +3H2SO4-----→K2SO4+2MnSO4+3H2O+5[O]
Oxidation half reaction: [2FeSO4 +H2SO4+[O] -----→Fe2(SO4)3 + H2O] ×5
Overall reaction: 2KMnO4 +10FeSO4+8H2SO4 -----→ K2SO4 +2MnSO4 + Fe2(SO4)3 +8 H2O
Preparation of 100mL of 0.05M Mohr’s salt solution:
Molecular mass of Mohr’s salt crystal is 392.1g
Molarity =Mass × 1000/Molar mass × volume required
0.05 = Mass×1000/392.1×100
Mass =0.05×392.1/10
=1.96g
a)Preparation of 0.05M Mohr’s salt solution:
Weigh exactly 1.96g of ferrous ammonium sulphate in a weighing bottle and transfer the same
into a 100ml standard flask containing 5ml of dil.H2SO4.Small amount of distilled water is added
and shaken well until it dissolves. The solution is made up to the mark using distilled water.
Stopper the flask and shake well for the uniform concentration of ferrous ammonium sulphate.
b)Estimation of molarity of KMnO4 Solution :
Procedure: Pipette out exactly 10ml of 0.05M Mohr’s salt solution into a clean conical flask.
Add one test tube full of dil.H 2SO4 .it is titrated against potassium permanganate solution taken
in the burette until a pale pink color is obtained.
The titration is repeated until concordant values are obtained.
Result: Strength of KMnO4 solution…………..M
Experiment No - 1
CHEMISTRY PRACTICAL 2
LAB MANUAL
3
Estimation of potassium permanganate using standard Mohr’s salt solution
Tabulation and calculation:
Titration of 10ml of 0.05 M FAS against KMnO4 Solution
In burette : KMnO4 solution
In Conical flask: 10ml 0.05 M FAS solution + one test tube full of Dil.H2SO4
Indicator : KMnO4 (Self Indicator)
End point :Colorless to pale pink
Agreeing volume of KMnO 4 =V1=………cm3
Where a1 and a2 are stoichiometric co-efficient of KMnO4 and FAS in the balanced chemical
equation (a1=5 and a2=1)
Trial Numbers 1 2 3
4
Initial burette readingFinal Burette reading
3Volume of KMnO used in cm4
www.vikascollege.com
(KMn0 )4 (FAS)
a M V1 1 1 = a M V2 2 2
Strength of KMn0 (M )4 1 = a M V2 2 2
a V1 1
= 1 x 0.005 x 105 x v1
= ________ M
VIKAS PRE-UNIVERSITY COLLEGE
AIM: To prepare a standard solution of oxalic acid and determine the strength of given
potassium permanganate solution.
PRINCIPLE: Potassium permanganate is a powerful oxiding agent .It oxidises oxalic acid in the
presence of Dil.H2SO4 to CO2 and H2O.Potassium permanganate acts as a self indicator.
REACTION:
Reduction half reaction: 2KMnO4 +3H2SO4-----→K2SO4+2MnSO4+3H2O+5[O]
Oxidation half reaction:[H2C2O4 +[O] -----→H2O +2CO2] ×5
Over all reaction: 2KMnO4 +3H2SO4+5H2C2O4 -----→ K2SO4 +2MnSO4 + 8 H2O +10CO2
Preparation of 100ml 0.05M oxalic acid:
Molecular mass of oxalic acid =126
Molarity =Mass × 1000/Molar mass × volume required
0.05 = Mass×1000/126×100
Mass = 126×100 ×0.05/1000
=0.63g
Mass required to prepare 100ml of oxalic acid solution is 0.63g.
a)Preparation of 0.05M oxalic acid:
Weigh exactly 0.63g of oxalic acid crystals and transfer the same into a 100ml standard flask. It
is dissolved in small amount of distilled water. The solution is then made up to the mark using
distilled water. stoper the flask and shake well for uniform concentration of oxalic acid.
b)Estimation of molarity of KMnO Solution: 4
Procedure: pipette out exactly 10ml of 0.05M oxalic acid solution into a clean conical flask.
Add one test tube full of dil.H2SO4 to prevent the formation of manganese dioxide.The mixture
is heated near to boiling. The hot solution is titrated against potassium permanganate solution
taken in a burette until a pale pink is obtained. The titration is repeated until concordant values
are obtained.
Result: Strength of the KMnO4 Solution= ………M
Experiment No - 2
CHEMISTRY PRACTICAL 2
LAB MANUAL
5
Estimation of potassium permanganate using standard oxalic acid solution
Tabulation and calculation:
Titration of 10ml of 0.05 M oxalic acid against KMnO4 Solution
In burette : KMnO4 solution
In Conical flask: 10ml 0.05 M oxalic acid solution + one test tube full of Dil.H2SO4
Indicator : KMnO4 (Self Indicator)
End point :Colourless to pale pink
Agreeing volume of KMnO4 =V1=………cm3
Where a1 and a2 are stoichiometric co-efficient of KMnO4 and Oxalic acid in the balanced
chemical equation (a1=5 and a2=2)
6
Trial Numbers 1 2 3
Initial burette readingFinal Burette reading
3Volume of KMnO used in cm4
www.vikascollege.com
(KMn0 )4 (oxalicacid)
a M V1 1 1 = a M V2 2 2
Strength of KMno (M )4 1 = a m v2 2 2
a M1 1
= 1 x 0.005 x 105 x v1
= ________ M
VIKAS PRE-UNIVERSITY COLLEGE
AIM: Preparation of pure sample of potash alum
PRINCIPLE: When a mixture of potassium sulphate and aluminum sulphate are saturated and
cooled, crystals of Potash alum is formed.
K2SO4+Al2(SO4)3 +24H2O ------→K2SO4 .Al (SO2 4) 3 24H2O
PROCEDURE: Dissolve in potassium sulphate (2.0g) and aluminium sulphate (8.0g) separately
in 10 mL of water.(since aluminum sulphate is less soluble in water add 3 to 4 drops of
conc.H2SO4 and warm)Mix the two solutions in china dish, it is heated to a small volume and
cooled. Colourless crystals of potash alum are formed.
Report: Yield of potash alum=……….g
Experiment No - 3
CHEMISTRY PRACTICAL 2
LAB MANUAL
7
Aim: Preparation of pure sample of Ferrous ammonium sulphate(FAS/Mohr’s salt)
Principle: When equimolar solutions of ferrous sulphate and ammonium sulphate are
mixed,subsequently evaporating the solution to crystallizations, the double salt seperates out.
FeSO4+( NH4)2SO4 +6H2O------→ FeSO4( NH4)2SO4 .6H2O
Procedure: In a 250mL beaker dissolves ferrous sulphate (7.0g) and ammonium sulphate
(3.5g) in 10mL of water containing 2-3mL of dil.H2SO4 to prevent the hydrolysis of ferrous
sulphate. Boil the solutions for 2-3 minutes and allow the beaker to cool slowly. Pale green
crystals of Mohr’s salt separates out. Filter and dry between the folds of the filter paper.
Report: Yield of Ferrous ammonium sulphate (Mohr’s salt) = ………..g
Experiment No - 4
8www.vikascollege.com
VIKAS PRE-UNIVERSITY COLLEGE
Inorganic salt analysis Aim: Systematic semi-micro qualitative analysis of a simple inorganic salt.
Experiment Observation Inference 1. The given salt is observed in the presence of light.
White crystalline Cu2+,Fe3+,Mn2+,Co2+,Ni2+,may be absent in salt.
Light pink crystalline Mn2+ salts may be present.
White amorphous CO32-,HCO3
-,or S2- may be present
2.Solubility in water: A pinch of salt+ 10 drops of water and shaken.
Soluble No inference possible Insoluble Salts of Na+,K+ or NH4
+ may be absent.
DETECTION OF ACID RADICALS: (ANION)
DETECTION OF FIRST GROUP ACID RADICS: (CO 32-)
A pinch of salt +dil.H2SO4
The gas liberated is passed into the test tube containing lime water.
Brisk effervescence I group acid radicals are present
Lime water turns milky Carbonate is present and confirmed
No brisk effervescence I group acid radicals are absent
DETECTION OF SECOND GROUP ACID RADICALS (Cl-,Br-,NO3-)
A pinch of salt+Conc.H2SO4 Colourless fuming gas is evolved, which gives dense white fumes with a glass rod dipped in NH4OH
II group acid radicals is present Chloride may be present
Reddish brown fumes and the solution turns brown
II group acid radical is present Bromide may be present
No characteristic observation
Chloride and Bromide are absent
Above solution + Copper turnings. Heated strongly.
Reddish brown fumes and the solution turns blue No reddish brown gas
II group acid radicals is present Nitrate may be present Nitrate is absent II group acid radicals absent.
CHEMISTRY PRACTICAL 2
LAB MANUAL
9
Experiment No - 5
DETECTION OF THIRD GROUP ACID RADICAL(SO42-)
a)Barium Chloride test: Clear solution of the salt in dil.HCl+2drops of Barium chloride solution.
A white precipitate insoluble in excess of dil.HCl
III group acid radical is present Sulphate is present and confirmed
b)Lead acetate test: Clear solution of the salt in water+Acetic acid+Lead acetate solution.
A white precipitate soluble in ammonium acetate solution
Sulphate is present and confirmed.
CONFIRMATORY TEST FOR CHLORIDE (Cl-)
1.Silver Nitrate test: Clear salt solution in dilute Nitric acid+3 drops of silver nitrate solution
A curdy white precipitate soluble in excess of ammonium hydroxide
Chloride is confirmed.
2.Chromyl Chloride test: A pinch of salt +potassium dichromate crystals +few drops of conc.H2SO4,mixture is heated The vapours are dissolved in water. To the yellow solution+3 drops of NH4OH+3 drops of acetic acid+2 drops of lead acetate solution
Reddish brown vapours of Chromyl Chloride are evolved
Yellow solution. Yellow precipitate
Chloride is confirmed.
CONFIRMATORY TEST FOR BROMIDE (Br-)
1.Silver Nitrate test: Clear salt solution in dilute nitric acid boil & cool +3 drops of silver nitrate solution.
A pale yellow precipitate partially soluble in excess of ammonium hydroxide
Bromide is confirmed
2.Orange globule test: Clear salt solution in water+3 drops of carbon tetrachloride+Chlorine water,shaken well.
Orange brown globule separates out
Bromide is confirmed
10www.vikascollege.com
VIKAS PRE-UNIVERSITY COLLEGE
CONFIRMATORY TEST FOR NITRATE(NO3-):
Brown ring test: 3 drops of clear salt solution in dil.H2SO4+3 drops of freshly saturated solution of Mohr’s salt+conc.H2SO4 is added carefully along the sides of the test tube
A brown ring is formed at the junction of two liquids
Nitrate is confirmed
DETECTION OF BASIC RADICALS (CATIONS):
TEST FOR AMMONIUM (NH4+) RADICAL: (ZERO GROUP ANALYSIS)
Action of NaOH: A pinch of the salt is heated with 5 drops of sodium hydroxide
A Pungent smell of ammonia which gives dense white fumes with a glass rod dipped in conc.HCl
NH4
+ may be present
No pungent smell of ammonia
NH4+ is absent
CONFIRMATORY TEST FOR AMMONIUM (NH4+) RADICAL:
Nessler’s reagent test: One drop of salt solution in water+3 drops of Nessler’s reagent
Brown precipitate is formed
NH4
+ is confirmed
PREPARATION OF ORIGINAL SOLUTION:
The given salt is taken in a test tube and it is dissolved in minimum amount of water or dil.HCl.
CHEMISTRY PRACTICAL 2
LAB MANUAL
11
DETECTION OF GROUP OF CATIONS:
Group 1: 1cm3 of OS + 1cm3 of dil.HCl in a test tube
No precipitate I group cations are absent
Group II: 1cm3 of OS + 1cm3 of dil.HCl+H2S solution is added
No precipitate II group cations are absent
Group III: 1cm3 of OS +2cm 3 of NH4Cl solution +NH4OH solution in excess
A Gelatinous white precipitate Al3+ may be present
No precipitate III group cations are absent
GroupIV: 1cm3 of OS +2cm 3 of NH4Cl solution +NH4OH solution in excess+H2S solution is added
A flesh coloured precipitate Mn2+ may be present
No precipitate IVgroup cations are absent
GroupV: 1cm3 of OS +2cm 3 of NH4Cl solution +NH4OH solution in excess +(NH4)2CO3 Solution
A white precipitate Ba2+,Sr2+,or ca2+ may be present
No precipitate V group cations are absent
Confirmatory test for Aluminium(Al3+)
a)Sodium hydroxide test: 1Cm3 of original solution+NaOH solution dropwise Above solution is treated with NH4Cl solution.
Gelatinous white precipitate soluble in excess of NaOH White gelatinous precipitate reappears
Al3+ is confirmed
b)Lake test: Original solution+blue litmus solution +NH4OH drop wise along the sides of the test tube
Blue precipitate floating in the colourless solution
Al3+ is confirmed
Confirmatory test for Manganous (Mn2+)
a)Sodium hydroxide test: 1cm 3 of original solution+NaOH solution dropwise.
White precipitate formed is insoluble in excess of NaOH and turns brown on exposure to air.
Mn2+ is confirmed
b) Lead dioxide test: 1cm 3 of OS +conc.HNO3+a pinch of lead dioxide,heated strongly and diluted with water.
Supernatant layer is pink in colour.
Mn2+ is confirmed
12www.vikascollege.com
VIKAS PRE-UNIVERSITY COLLEGE
Confirmatory test for V group cations:
a)Potassium chromate test: 1cm3 of original solution+acetic acid + potassium chromate solution
Yellow precipitate Ba 2+ is confirmed
No yellow precipitate Ba2+ is absent
b)Ammonium sulphate test: 1cm 3 of original solution+ammonium sulphate solution,warm.
White precipitate Sr2+ is confirmed
No white precipitate Sr2+ is absent
c)Ammonium oxalate test: 1Cm3 of original solution+5 drops of NH4OH +Ammonium oxalate solution.
White precipitate Ca2+ is confirmed
Flame test: A pinch of salt +few drops conc.HCl and made into a paste. The paste is held to the flame with the help of a platinum wire.
a)Apple green colour is imparted to the flame b)Crimson red colour is imparted to the flame c)Brick red colour is imparted to the flame
Ba2+ is confirmed Sr2+ is confirmed Ca2+ is confirmed
Analysis of VI group basic radical:
Confirmatory test for Magnesium (Mg2+) 1)Disodium hydrogen phosphate test: 1cm 3 of original solution+2cm3 of NH4OH+5 drops of disodium hydrogen phosphate.The side of the test tube is scratched with glass rod.
White crystalline precipitate
Mg2+ is confirmed.
2) Sodium hydroxide test: 1cm 3 of original solution+NaOH Solution.
White precipitate insoluble in NaOH solution
Mg2+ is confirmed.
Report: The given inorganic salt contains,
Anion is ……………………(……..).It belongs to group……….
Cation is…………………….(…….).It belongs to group……….
Hence the given salt is…………………………(……….)
CHEMISTRY PRACTICAL 2
LAB MANUAL
13
Aim: Test for the functional group present in organic compounds
1)Test for unsaturation:
Experiment Observation Inference a)Baeyer’s test: Organic compound is dissolved in water or acetone+a few drops of 1%alkaline KMnO4 Solution. b)Bromine water test: Organic compound is dissolved in CCl4 +2% Solution of bromine in CCl4 dropwise.
Pink colour of KMnO4
Orange red colour of bromine discharges
The given organic compound is unsaturated
The given organic compound is unsaturated.
2) Test for Alcoholic (R-OH) group:
a) Ceric ammonium nitrate test: Organic compound+few drops of Ceric ammonium nitrate solution.Shaken well. b)Esterification : Organic compound+acetic acid+2 drops of conc.H2SO4 keep it in boiling water bath for 5 minutes.Pour the mixture in Na2CO3 solution
A pink colour or red colour appears.
A fruity smell
Alcoholic (-OH)group present
Alcoholic (-OH)group present
3) Test for Phenolic (Ar-OH) group:
a)Neutral FeCl3 test: Organic compound in a test tube +a few drops of neutral FeCl3 solution.
A violet colour
The given organic compound contains a phenolic group.
b) Phthalein test: Organic compound +phthalic anhydride +conc.H2SO4,heated and added to NaOH
A pink colour
The given organic compound contains a phenolic group.
Experiment No - 6
14www.vikascollege.com
VIKAS PRE-UNIVERSITY COLLEGE
4) Test for Aldehydic (-CHO)group:
a)2,4-DNP test: Organic compound in a test tube +2,4-Dinitrophenyl hydrazine solution. b)Schiff’s test: Organic compound in a test tube+Schiff’s reagent. c)Tollen’s test: Organic compound in a test tube +Tollen’s reagent keep in a boiling water bath d) Benedict’s /Fehling’s test: Organic compound + Benedict’s /Fehling’s solution and heated.
Orange yellow crystalline precipitate is formed. A pink colour is obtained A black precipitate or silver mirror is formed A brick red precipitate is obtained
The given organic compound contains aldehydic or a ketonic group. The given organic compound contains aldehydic group. The given organic compound confirms the presence of an aldehydic group The given organic compound contains aldehydic group.
5)Test for Ketonic (-CO-)group:
a)m-dinitrobenzene test: Organic compound in a test tube+m-dinitrobenzene(s)+dil.NaOH solution and shake well.
A violet colour which slowly fades
The given organic compound contains Ketonic group.
b) Sodium nitroprusside test: Organic compound in a test tube +Sodium nitroprusside solution +NaOH solution
A wine red colour is obtained
The given organic compound confirms the presence of a ketonic group.
CHEMISTRY PRACTICAL 2
LAB MANUAL
15
6)Test for carboxylic (-COOH-)group:
a)Litmus test: Organic compound in a test tube+blue litmus paper. b) Sodium Bicarbonate test: Organic compound in a test tube +NaHCO3 solution. c)Esterification: Organic compound in a test tube +ethyl alcohol+2 drops of conc.H SO ,keep it in a 2 4
boiling water bath for 5 minutes and cool,pour into Na2CO3.
Blue litmus paper turns red. Brisk effervescence of CO2
A fruity smell
The given organic compound contains a carboxylic group The given organic compound contains a carboxylic group. The given organic compound confirms the presence of carboxylic group.
7) Test for Amino group(-NH 2) group:
a) Carbylamine test: Organic compound in a test tube +a few drops of chloroform +alcoholic potash.Warm. d)Diazotisation (test for aromatic primary amine) Organic compound dissolved in dil.HCl and cooled in ice .+ice cooled NaNO2 solution +ice cooled solution of β-naphthol in NaOH.
An intolerable smell of isocyanide. A red or orange dye is obtained
The given organic compound is a primary amine and confirms the presence of amino group. Primary aromatic amino group is present.
16www.vikascollege.com
VIKAS PRE-UNIVERSITY COLLEGE
Aim: Preparation of Acetanilide from aniline.
Principle: Acetanilide is prepared by the acetylation of aniline with acetic anhydride in the
presence of acetic acid.
Procedure: Take 10mL of aniline in a round bottom flask.Add 10mL of acetic anhydride and
10mL of acetic acid with constant shaking.The flask is fitted with a reflux condenser and heated
on a sand bath for 10-15 minutes.the flask is cooled and the mixture is added to ice cold water
taken in a 250mL beaker, white solid seperates out.It is filtered,the white solid is impure
acetanilide.
Recrystallisation of acetanilide :
The crude sample is recrystalised using hot water containing a small quantity of ethyl alcohol.
Report:
1.Yield of acetanilide = g
2.Melting point of acetanilide =113oC
Experiment No - 7
CHEMISTRY PRACTICAL 2
LAB MANUAL
17
Aim: Preparation of iodoform crystals.
Principle: Iodoform is prepared by mixing iodine in acetone and 10%Sodium hydroxide
solution.
CH3COCH3 +4I2 +6NaOH------→CHI3 +CH3COONa +5NaI
Procedure: Take 2mL of acetone in a clean conical flask add 5mL of iodine solution and 5mL
of 10%Sodium hydroxide solution to the flask slowly, shake until yellow crystals of iodoform is
formed.
The crystals are filtered, washed and dried between the folds of the filter paper.
Report:
1.Yield of iodoform= g
2.Melting point of iodoform=121oC
Experiment No - 8
18www.vikascollege.com
VIKAS PRE-UNIVERSITY COLLEGE
Preparation of Lyophilic and Lyophobic sol
Aim: To prepare a)Lyophilic sol and b)Lyophobic sol
a)Preparation of Lyophilic sol:
1)Egg Albumin sol: It consists of egg protein dispersed phase and water dispersion medium.
Procedure: 5g of NaCl is dissolved in 100mL H2O in a beaker to get 5%NaCl solution.Egg
Albumin is added into NaCl solution with constant shaking until a colloidal solution of egg
albumin is obtained.
2)Starch sol: In starch sol solid starch is the dispersed phase and water acts a dispersion
medium.
Procedure: A paste of 500mg of starch is prepared in hot water in a beaker.The paste of starch
is added into boiling water taken in another beaker with constant stirring for about 10 minutes
until a colloidal solution of starch is obtained.
b) Preparation of Lyophobic sol:
1.Ferric hydroxide sol: It consists of Fe(OH)3 as dispersed phase and water as dispersion
medium
Procedure: 2g of FeCl3 are dissolved in 100mL of water taken in a beaker to get 2% FeCl3
solution. The solution is added drop by drop into boiling water taken in a separate beaker with
constant stirring until a brown colloidal solution of of Fe(OH)3 is obtained.
2.Arsenous sulphide sol: It consists of As2S3 dispersed phase and water dispersion medium.
Procedure: 0.2g of arsenous oxide is dissolved in 100 mL of boiling water to get 0.2% As2O3
solution, H2S is passed into it till the solution smells H2S.The solution is gently warmed to
remove the excess of H2S and filtered to get the sol.
Experiment No - 9
CHEMISTRY PRACTICAL 2
LAB MANUAL
19
Study the role of emulsifying agent in stabilising the emulsions of different oils
Aim: To study the role of emulsifying agent in stabilising the emulsions of different oils
An emulsion contains liquid dispersed phase and liquid dispersion medium
Soap solution is prepared by dissolving 1g of soap powder in 10ml water.
10 drops each of mustard oil,linseed oil,castor seed oil and machine oil are taken in four
separate test tubes A,B,C and D.And 15ml of distilled water is added to each of the test
tube.
The solutions in the test tube are shaken well and left for settling to get the
emulsion . The time taken for the formation o f separate layer s in each tes t tube is
recorded using a stop clock.
The soap solution is added in drops into each test tube and shaken well for about 5 minutes.
The time taken for the formation of separate layer is recorded using a stop clock.
Tabulation:
Test tube
Oil taken Time taken for the formation of separate layers
Without soap solution
With soap solution
A Mustard oil B Linseed oil
C Castor seed oil D Machine oil
Experiment No -10
20www.vikascollege.com
VIKAS PRE-UNIVERSITY COLLEGE
Determination of heat of neutralization of Hydrochloric acid with Sodium hydroxide
Aim: Determination of heat of neutralization of Hydrochloric acid with Sodium hydroxide
Principle: The heat of neutralization is the amount of heat evolved when one gram equivalent
of an acid is neutralized by 1 gram equivalent of a base.
Procedure: 100cm3 of 1N HCl and 100 cm3 of 1N NaOH are taken in separate polythene
bottles, each fitted with thermometer and a stirrer. Both the solutions are kept in a water bath
maintained at lab temperature for 15 minutes. The temperatures are noted. When both the
solutions attain the same temperature, then Sodium hydroxide is added to hydrochloric acid.
The bottle is stoppered and stirred well. The maximum temperature attained is noted.
Report: Heat of neutralization of HCl is -57.3kJ/mol
Experiment No - 11
CHEMISTRY PRACTICAL 2
LAB MANUAL
21
Calculations:
Initial temperature,T10C = 25.20C+273=298.2K
Final temperature, T20C = 25.880C+273=298.88K
Rise in temperature =(T2-T1)K = 298.88-298.2 =0.682K
Volume of the solution = 100cm3 +100cm3 =200cm3
Mass of the solution 200g or 0.2kg
Specific heat of water or the solution =4200J/kg/K
Heat liberated during the reaction =mass of the solution × specific heat × rise in temperature
q = 0.2×4200 × =(T2-T1) = q J =0.2×4200×0.682
=0.573 J
1N means 1000cm3 of the solution contains 1 gram eq.mass.
Since 100cm3 of 1mol hydrochloric acid is taken,
Amount of HCl taken =1×100/1000 =0.1g eq.mass.
Amount of heat evolved when 1 gram equivalent mass of HCl is neutralized
q/0.1 =Q J = 0.573J/0.1 = 57.3kJ/eq
Heat liberated is 57.3kJ/equivalent
Heat of neutralisation of Hydrochloric acid = -57.3kJ/mol
22www.vikascollege.com
VIKAS PRE-UNIVERSITY COLLEGE
CHEMISTRY PRACTICAL 2
LAB MANUAL
1. Do not enter the laboratory when an instructor/lab assistant is not present or the lab door is closed. Finish your lab work on time to clean up before the end of the scheduled lab period.
2. Perform only authorized experiments. Parents, Visitors are not permitted to be with you while you do your lab work.
3. Wear personal protective equipment (PPE) at all times in the chemistry laboratory including when cleaning up following an experiment.
4. Shoes which offer reasonable protection will be worn while in the laboratory. Shoes must cover the entire foot, including the toes, the top of the foot, and the heel.
5. Hair that is longer than shoulder-length must be tied back at all times.
6. Eating, drinking, mouth rinsing, applying cosmetics or lip balm or handling contact lenses is prohibited in the lab areas. No chewing gum is allowed.
7. Be considerate of others working in the laboratory. Do not distract others while conducting experiments or accomplishing lab activities. When finished with equipment or materials to be shared with others, make the equipment or materials available to others as quickly as possible.
8. Before leaving the lab, clean all equipment, glassware and the work area you have been using. Return equipment and glassware to their proper places in the laboratory.
9. Know the location and proper use of safety equipment in the laboratory.
10. Immediately notify the lab instructor of chemical spills, broken glass or other hazards. Do not attempt to clean up such mishaps/materials by yourself without first alerting your instructor/lab supervisor.
11. Immediately notify the instructor/lab supervisor of any accidents, injuries, or situations in which exposure to human blood or other potentially infectious materials in the laboratory has occurred, regardless of how minor they may appear to be.
12. You may be exposed to potentially hazardous materials in the process of completing your required laboratory activities. Persons with specific health concerns such as wearers of contact lenses, persons with known hypersensitivities, etc. should consult their personal physician for advisement about potential risks before continuing in the course.
SAFETY PROCEDURE IN LAB
SUCCESS GUARANTEED ONLY AT VIKAS