chemical analysis lab manual

24
1. ESTIMATION OF ACID VALUE (ANALYSIS OF OIL) AIM To calculate the number of milligrams of potassium hydroxide required to neutralize the free fatty acid in 5 gm of oil. THEORY Acid value indicates the proportion of free fatty acid present in an oil or fat and may be defined as the number of milligrams of caustic potash required to neutralize the acid in 1 gm of the sample. The normal acid value for most samples lies within 0.5. If any titrable acid other than a fatty acid is present in the sample, it will be an error. A high acid value indicates a stale oil or fat stored under improper conditions. PROCEDURE STANDARDIZATION OF KOH 1) Take 20 ml of 0.1 N oxalic acid solution in a 250 ml conical flask. 2) Add 1 or 2 drops of phenolphthalein indicator to this solution. 3) Titrate this solution against KOH taken in a burette. 4) The appearance of pink color indicates the end point. 5) From the volume of the KOH solution in burette, find the normality of KOH. EXPERIMENTAL PROCEDURE 1) Weigh 5 gm of oil and transfer it into 250 ml conical flask. 2) Add 50 ml of neutralized alcohol solution to the oil solution. 3) Heat this mixture for 10 minutes by using the heater. 4) Take the solution after 10 minutes and add 1 or 2 drops of phenolphthalein indicator. 5) Titrate this against the KOH solution from the burette. 6) The appearance of pink color indicates the end point.

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Page 1: Chemical Analysis Lab Manual

1. ESTIMATION OF ACID VALUE (ANALYSIS OF OIL)

AIM To calculate the number of milligrams of potassium hydroxide required to neutralize the free fatty acid in 5 gm of oil. THEORY Acid value indicates the proportion of free fatty acid present in an oil or fat and may be defined as the number of milligrams of caustic potash required to neutralize the acid in 1 gm of the sample. The normal acid value for most samples lies within 0.5. If any titrable acid other than a fatty acid is present in the sample, it will be an error. A high acid value indicates a stale oil or fat stored under improper conditions. PROCEDURE STANDARDIZATION OF KOH

1) Take 20 ml of 0.1 N oxalic acid solution in a 250 ml conical flask. 2) Add 1 or 2 drops of phenolphthalein indicator to this solution. 3) Titrate this solution against KOH taken in a burette. 4) The appearance of pink color indicates the end point. 5) From the volume of the KOH solution in burette, find the normality of KOH.

EXPERIMENTAL PROCEDURE

1) Weigh 5 gm of oil and transfer it into 250 ml conical flask. 2) Add 50 ml of neutralized alcohol solution to the oil solution. 3) Heat this mixture for 10 minutes by using the heater. 4) Take the solution after 10 minutes and add 1 or 2 drops of phenolphthalein indicator. 5) Titrate this against the KOH solution from the burette. 6) The appearance of pink color indicates the end point.

Page 2: Chemical Analysis Lab Manual

ESTIMATION OF ACID VALUE (ANALYSIS OF OIL) TABULAR COLUMN Titration I : Standardisation of Potassium hydroxide Burette solution : KOH Pipette solution : Oxalic acid Indicator : Phenolphthalein End point : Appearance of pink colour

BURETTE READING (ml)

S.NO VOLUME OF OXALIC ACID (ml) INITIAL FINAL

VOLUME OF KOH CONSUMED (ml)

Concordant Value (ml)

1

2

CALCULATION (1)

Volume of oxalic acid (V1)=

Normality of oxalic acid (N1)=

Volume of KOH consumed (V2)=

Normality of KOH consumed (N2)= V1 N1 / V2

Normality of KOH (N2) = _______________. Titration II : Estimation of acid value Burette solution : KOH Pipette solution : Oil + 50 ml of neutralized alcohol Indicator : Phenolphthalein End point : Appearance of pink colour

BURETTE READING (ml) S.NO WEIGHT OF OIL

(gm) INITIAL FINAL

VOLUME OF KOH (ml)

Concordant Value (ml)

1

2

CALCULATION(2)

Acid value = SampleOilofWeight

KOHofwtEqKOHofNormalityKOHofml .××

Equivalent weight of KOH = 56.11

Acid Value = __________.

RESULT The acid value of the given oil sample was found to be___________.

Page 3: Chemical Analysis Lab Manual

2. ESTIMATION OF SAPONIFICATION VALUE (ANALYSIS OF OIL )

AIM To calculate the number of milligrams of potassium hydroxide required to completely saponify 1 gm of Oil. THEORY

Saponification value indicates the average molecular weight of a fat or oil. The

saponification value may be defined as the number of milligrams of caustic potash required to

neutralize the fatty acids obtained by complete hydrolysis of one gram of oil or fat. Thus

saponification value gives us information whether an oil or fat contains high proportion of

lower or higher fatty acids. For eg., butter has a large proportion of lower fatty acids than lard

and tallow, and has high saponification value. Coconut oil also has a comparatively higher

saponification value.

Applications of saponification value:

Saponification value gives us an idea about the molecular weight of fat or oil.

Oil x Saponification Value = Amount of Lye needed to make soap.

PROCEDURE

1) Weigh 1 gm of oil and transfer into the round bottomed flask.

2) Add 20 ml of 0.5 N alcoholic KOH solution to the round bottomed flask.

3) Follow the above procedure without taking oil for blank titration.

4) Reflux both round bottomed flasks for 1 hour.

5) After reflux, allow both the round bottomed flasks to cool.

6) Titrate both the samples using 0.5 N HCl with phenolphthalein indicator.

7) The disappearance of pink indicates the end point.

RESULT

The saponification value of the given oil sample was found to be_____________.

Page 4: Chemical Analysis Lab Manual

TABULAR COLUMN Titration : Estimation of saponification value Burette solution : HCl Flask solution : Alcoholic KOH (with and without oil) Indicator : Phenolphthalein End point : Disappearance of pink colour

BURETTE READING (ml)

S.NO VOLUME OF OIL

SOLUTION (gl)

VOLUME OF ALCOHOLIC

KOH SOLUTION (ml) INITIAL FINAL

TITER VALUE

((ml)

1

2

Blank ( Without Oil)

CALCULATION Saponification Value = (Titre value of blank in ml – Titre value of sample in ml) x NKOH x Equivalent wt of KOH Weight of the sample Saponification value = _________________

Page 5: Chemical Analysis Lab Manual

3. ESTIMATION OF IODINE VALUE (ANALYSIS OF OIL)

AIM To determine the amount of unsaturation present in the given oil. ( To determine the iodine value of an oil) PRINCIPLE The Iodine number is defined as the number of grams of iodine which will add to 100 grams of fat or oil. Iodine value shows the degree of unsaturation of the constituent fatty acids in an oil or fat and is thus a relative measure of the unsaturated bonds present in the oil or fat. Iodine value is expressed in grams of iodine absorbed by 100 gms of oil or fat. Unsaturated compounds absorb iodine ( in suitable form) and form saturated compounds. The amount of iodine absorbed in percentage is the measure of unsaturation in the oil. No oil has zero iodine value and oils are classified as drying, semi drying and non drying on the basis of iodine value. Oleic acid containing 1 double bond absorbs 90% of iodine, linoleic acid (2 double bonds) absorbs 181% iodine and linolenic acid (3 double bonds) absorbs 274% iodine. Non drying oils have 1 double bond and absorbs iodine below 90%. Semi drying oils contain some proportion of double bonds and have iodine value below 140.Iodine value for coconut oil is 8, for olive 88, for human fat 105, for linseed about 200. CHEMICALS REQUIRED Wij’s Solution: Dissolve separately 7.5 gm of AR Iodine tetrachloride and 8.5 gm of resublimed iodine in glacial acetic acid by warming on a water bath. Mix the two solutions and dilute to 1 litre with glacial acetic acid in cold. Potassium iodide solution ( 15%) Dissolve 15 gm of AR potassium iodide in 100 ml of water. Sodium thiosulphate solution (0.1 N) Dissolve 25 gm of AR sodium thiosulphate crystals ( Na2S2O3 5H2O) in a 1 litre of distilled water. Starch indicator solution 1 ml of starch in 100 ml boiling water.

Page 6: Chemical Analysis Lab Manual

PROCEDURE STANDARDIZATION OF SODIUM THIOSULPHATE SOLUTION

1. Pipette out 20 ml of 0.1 N potassium dichromate solution into a clean conical flask. 2. Add 1 test tube of dilute H2SO4 and 10 ml of 15% KI solution to the conical flask. 3. Titrate against thiosulphate from the burette until it turned into pale yellow. 4. Add 1 ml of starch indicator and titrate against thiosulphate solution. 5. End point is disappearance of blue color.

EXPERIMENTAL PROCEDURE

1. Weigh 0.5 gm of oil and transfer into Iodine flask.

2. Add 10 ml of chloroform and warm slightly and cool for 10 minutes

3. Add 25 ml of Wij’s solution in the same flask and shake vigorously.

4. Then allow the flask to stand for half an hour in dark place.

5. Add 10 ml of KI solution and after that titrate the solution against 0.1 N Sodium thiosulphate solution until the appearance of yellow color.

6. Add 1 ml of starch indicator and again titrate against the sodium thiosulphte solution from the burette.

7. Disappearance of blue color indicates end point.

8. Repeat the above procedure without taking sample(ie Oil) and note the corresponding reading for blank titration.

RESULT The iodine value of the given oil sample was found to be =___________.

Page 7: Chemical Analysis Lab Manual

TABULAR COLUMN Titration I Standardisation of Sodium thiosulphate: Burette solution :Sodium thiosulphate Pipette solution :Potassium dichromate Additional solution :1 test tube of dil H2SO4 solution Indicator : Starch End point :Disappearance of blue

BURETTE READING (ml)

VOLUME OF SODIUM THIOSULPHATE SOLUTION (ml)

S.NO VOLUME OF K2Cr2O7 SOLUTION

(ml) INITIAL FINAL

1

2

CALCULATION Volume of K2Cr2O7 ( V1) = Normality of K2Cr2O7 (N1) = Volume of sodium thiosulphate solution (V2) = Normality of sodium thiosulphate solution ( N2) = (V1 x N2) / V2

Titration II Estimation of Iodine value: Burette solution : Std. Sodium thiosulphate solution Pipette solution : 20 ml of oil Additional solution : 25 ml of Wij’s solution + 20 ml of KI ( 15%)+50 ml of water Indicator : Starch End point : Disappearance of blue color

BURETTE READING (ml)

VOLUME OF SODIUM THIOSULPHATE SOLUTION

(ml)

S.NO VOLUME OF SOLUTION (ml)

INITIAL FINAL 1

Oil solution V2 =

2

Blank V1 =

CALCULATION: Iodine value = (V1 – V2) x N1 x Equivalent weight of Iodine x 100 W x 1000 where V1 = Volume of thiosulphate required by blank,ml N1 = Normality of thiosulphate V2 = Volume of thiosulphate required by sample,ml W= Weight of the sample Iodine value = _____________.

Page 8: Chemical Analysis Lab Manual

4. ESTIMATION OF SILICA CONTENT (ANALYSIS OF CEMENT)

AIM To estimate the silica content in the given cement sample APPARATUS REQUIRED Crucible, Desiccator, Beaker, Water bath, No 40 Wattman filter paper, Pipette, Electric Bunsen Burner, Stirrer CHEMICALS REQUIRED Given sample of Portland cement, 1:1 HCl. PROCEDURE

1) Weigh 2 gm of cement accurately and transfer into china dish 2) Add 2 ml of water to prevent lumping 3) Add 10 ml of 1:1 HCl to this and allow to digest for 10 minutes 4) Add 50 ml of water and transfer the contents from china dish into beaker 5) Add 50 ml of 1:1 HCl into beaker to make it to acidic medium 6) Then filter through No:40 Wattman filter paper 7) Incinerate in the pre weighed crucible 8) Cool it in a desiccator. 9) Weigh the crucible with its content. 10)Find out amount of silica.

CALCULATION: Weight of cement taken (w) = g Weight of empty crucible (a) = g Weight of silica + crucible (b) = g % of silica = ( b – a ) x100 w % of silica = ____________ RESULT The amount of silica content was found to be =______________.

Page 9: Chemical Analysis Lab Manual

5) ESTIMATION OF MIXED OXIDE CONTENT (ANALYSIS OF C EMENT)

AIM To estimate the mixed oxide content in the given cement sample APPARATUS REQUIRED Crucible, Desiccator, Beaker, Water bath, No 40 Wattman filter paper, Pipette, Electric Bunsen Burner, Stirrer CHEMICALS REQUIRED Given sample of Portland cement, 1:1 HCl, 15% NaOH solution, NH4Cl, NH3, Ammonium oxalate etc. PROCEDURE 1) Weigh 2 gm cement and transfer into a china dish 2) Add 2 ml of water to prevent lumping 3) Add 10 ml of 1:1 HCl to this and allow to digest for 10 minutes. 4) Add 50 ml of water and transfer the contents from china dish to a beaker 5) Add 50 ml of 1:1 HCl to this beaker to make the acidic medium 6) Filter the solution through No 40 Wattman filter paper 7) Collect the filtrate in a beaker and make up to 250 ml 8) Pipette out 100 ml of the above solution into a beaker and boil it 9) Add 2 gm of NH4Cl to avoid the precipitation of Ca and Mg compounds 10) Add 20 ml of NH3 to the boiling solution to make the solution alkaline 11) Boil the solution for about 5 minutes until a pale brown jelly precipitate formed 12) Cool the solution and filter the solution into No 40 Wattman filter paper. 13) Then incinerate the in a preweighed crucible and cool it in desiccator. 14) Obtain the amount of mixed oxide content by difference in weight. CALCULATION: Weight of cement taken (w) = g Weight of empty crucible (a) = g Weight of mixed oxide content + crucible (b) = g % of mixed oxide content (Fe2O3 + Al2O3) = ( b – a ) x250 x100 w x 100 % of Mixed oxide content = ____________ RESULT The amount of mixed oxide content was found to be=_____________.

Page 10: Chemical Analysis Lab Manual

6) ESTIMATION OF CALCIUM OXIDE CONTENT

AIM To estimate the calcium oxide content in the given cement sample APPARATUS REQUIRED Crucible, Desiccator, Beaker, Water bath, No 40 Wattman filter paper, Pipette, Electric Bunsen Burner, Stirrer. CHEMICALS REQUIRED Given sample of Portland cement, 1:1 HCl, 15% NaOH solution, NH4Cl, NH3, Ammonium oxalate etc. PROCEDURE

1) Weigh 2 gm cement and transfer into china dish. 2) Add 2 ml of water to prevent lumping. 3) Add 10 ml of 1:1 HCl to this and allow to digest for 10 minutes. 4) Add 50 ml of water to transfer the contents from china dish to a beaker. 5) Add 50 ml of 1:1 HCl to this beaker to make the acidic medium 6) Filter the solution through No 40 Wattman filter paper 7) Collect the filtrate in a beaker and make it up to 250 ml 8) Pipette out 100 ml of above solution into a beaker and boil it 9) Add 2 gm of NH4Cl to avoid the precipitation of Ca and Mg compounds 10) Add 20 ml of NH3 to the boiling solution to make the solution alkaline 11) Boil the solution for about 5 minutes until a pale brown jelly precipitate formed

12) Cool the solution and filter the solution into No 40 Wattman filter paper. 13) Heat the collected filtrate 14) Dissolve 1 gm of ammonium oxalate in 10 ml of boiling water and add to the boiling filtrate 15) White precipitate of oxalate is formed during the above procedure. 16) Then filter through No 40 Wattman filter paper. 17) Incinerate the preweighed crucible and cool it in a desiccator. 18) Find the amount of calcium oxide content from the difference in weight. ESTIMATION OF CALCIUM OXIDE CONTENT

Weight of cement taken (w) = )g) Weight of the empty crucible (a) = (g) Weight of crucible + calcium oxide (b) = (g) % of calcium oxide content = ( b – a ) x 250 x 100 w x 100 RESULT The amount of calcium oxide content was found to be =_______________.

Page 11: Chemical Analysis Lab Manual

7) ESTIMATION OF TOTAL FATTY MATTER CONTENT

AIM To analyze the sample of the given soap and to determine the total fatty matter content APPARATUS REQUIRED Grinding bowl, Beaker, Stirrer, Glass plate, Conical flask, Pipette, Burette, Standard flask, Separating funnel, Water bath, Electric Bunsen Burner, Funnel, Desiccator, China dish. CHEMICALS REQUIRED Given sample of soap, Water, Chloroform, Sodium carbonate, 0.5 N HNO3 PROCEDURE

1) Weigh 5 gm of soap accurately and transfer into 250 ml beaker 2) Add 100 ml hot water to completely dissolve the soap. 3) Add 40 ml of 0.5 N HNO3 until contents were slightly acidic 4) Heat the mixture over water bath until the fatty acids were floating as a layer above the solution 5) Then cool it suddenly in ice water in order to solidify the fatty acids and separate them. 6) Add 50 ml of chloroform to the remaining solution and transfer it to a separating funnel. 7) Shake the solution and allow the solution to separate into 2 layers. Drain the bottom layer. 8) Add 50 ml of chloroform to the remaining solution in the separating funnel 9) Separate the fatty acid dissolved chloroform again as in the previous case and transfer it to the collected fatty matter. 10) Weigh the fatty matter in a pre weighed china dish. 11) Allow the contents to evaporate and weigh the residue. 12) From the difference in weight, calculate the % of fatty matter in the given soap sample.

CALCULATION Weight of the china dish (x) = _____________ Weight of china dish + Soap after drying (y)=______________ % of fatty mater = (y – x) * 100 Weight of soap sample % of fatty matter = ___________. RESULT The percentage of total fatty matter present in the given sample of soap was found to be_________.

Page 12: Chemical Analysis Lab Manual

8) ESTIMATION OF TOTAL ALKALI CONTENT

AIM To analyze the given soap sample and to determine the total alkali content APPARATUS REQUIRED Beaker, Stirrer, Glass plate, conical flask, Pipette, Burette, Standard flask, separating funnel. CHEMICALS REQUIRED Given sample of soap, Diethyl Ether, Sodium Chloride, 100 g/l aqueous solution, Sulphuric acid, 1N aqueous solution, Sodium Hydroxide, 1N aqueous solution, Methyl orange indicator. PROCEDURE

1) Weigh about 5 gm of soap. 2) Add 100 ml distilled water. 3) Gently heat until complete dissolution. 4) Transfer quantitatively to a separating funnel. 5) Add few drops of methyl orange indicator 6) Add 10 ml of H2SO4 until solution becomes pink. 7) Allow to cool at room temperature. 8) Add 100 ml diethyl ether. 9) Shake vigorously for one minute. 10) Allow to stand still two phases are completely separated. 11) Take the bottom of the aqueous solution layer into a second separating funnel. 12) Carry out the second extraction of the acid solution by shaking with diethyl ether. 13) Take the aqueous acid solution into a conical flask. Wash twice with 50 ml of 1N

Sodium chloride solution by shaking for a minute. 14) Filtrate the resulting conical flask solution with Sodium hydroxide.

The total alkali content, expressed as a percentage (m/M), is given by the formula:

[ ]m

TVTV

m

m 22114%

−=

Calculation: Volume of H2SO4 solution (V1) = ml Volume of NaOH solution (V2) = ml Normality of H2SO4 (T1) = N Normality of NaOH (T2) = N Mass of Soap (M) = g

RESULT The total alkali content of the given soap sample was found to be___________.

Page 13: Chemical Analysis Lab Manual

9. ESTIMATION OF RESIDUAL CHLORINE IN WATER

AIM To estimate the amount of residual chlorine in water APPARATUS REQUIRED Burette, Pipette, Conical flask, Pestle and mortar. CHEMICALS REQUIRED Potassium iodide, Sulphuric acid, Sodium thio sulphate, Bleaching powder, Starch Indicator PROCEDURE

1) Weigh about 0.5 gm of bleaching powder and transfer into mortar 2) Add small amount of water to the bleaching powder and grind them well with the help of pestle 3) Allow the solution to settle in a few minutes, transfer the liquid portion into a 250 ml standard flask. 4) Repeat the above procedure until all the contents of bleaching powder are completely transferred into 250 ml flask. 5) Add additional water to make it exactly 250 ml. 6) Pipette out 10 ml of the Bleaching powder solution (made up solution) into a conical flask 7) Add 10 ml of 15% KI and 10 ml of 1 N H2SO4 to this solution and then shake well. 8) Titrate against 0.1 N sodium thiosulphate solution until yellow color appeared 9) Add 1 or 2 drops of starch indicator that turns the solution blue. 10) Then titrate against sodium thiosulphate solution until the blue color disappears.

RELATED EQUATIONS 2 KI + Cl2 � 2 KCl + I2 KI + I2 � KI3 I2 + 2 Na2S2O3 � 2 NaI + Na2S4O6 I2 + Starch � Complex having deep blue complex

RESULT The amount of Residual chlorine in the water sample was found to be _________%.

Page 14: Chemical Analysis Lab Manual

Titration I: Standardization of Sodium thio sulphate solution Burette solution : Sodium thio sulphate solution Pipette solution : Standard K2Cr2O7 solution Additional solution : 10 ml of H2SO4 + 10 ml of 15% KI Indicator : Starch End point : Blue to green

BURETTE READING (ml)

S.NO VOLUME OF K2Cr2O7 SOLUTION (V1) ml INITIAL FINAL

VOLUME OF SODIUM THIO SULPHATE SOLUTION

(ml)

1

2

Volume of K2Cr2O7 (V1) = Normality of K2Cr2O7 (N1) = Volume of Na2S2O3 (V2) = Normality of Na2S2O3 (N2) = (V1xN1) / V2 Titration II: Estimation of Available Chlorine: Burette solution: Standard Sodium Thio sulphate solution Pipette solution : 10 ml of Bleaching powder solution + 10 ml of H2SO4 + 10 ml of 15%KI Indicator : Starch End point : Blue to colorless

BURETTE READING (ml) S.NO VOLUME OF BLEACHING POWDER SOLUTION (V3) ml

INITIAL FINAL VOLUME OF SODIUM THIO SULPHATE SOLUTION (V4)ml

1

2

Page 15: Chemical Analysis Lab Manual

CALCULATION 1 equivalent of Cl2 = 1 Equivalent of I2 1000 ml of 1 N Na2S2O3.5H2O solution is equivalent to 35.46 g of Cl2 1000 ml of 0.1 N Na2S2O3.5H2O solution is equivalent to 3.546 g of Cl2 1 ml of 0.1 N Na2S2O3.5H2O is equivalent to 3.546 x 10-3 g of Cl2 Volume of Na2S2O3 solution consumed V4 = ________ ml V4 ml of N2 normality solution of Na2S2O3.5H2O is equivalent to (X1) = (V4 x N2 x 3.546 x 10-3) / (1 x 0.1) = _________ g. 10 ml of Bleaching powder solution contains X1 g of Cl2. 250 ml of Bleaching powder solution contains = (X1 x 250) / 10 = X2 g of Cl2. Weight of bleaching powder taken = w g % of chlorine = X2 x 100 / w = _________ %

Page 16: Chemical Analysis Lab Manual

10. ESTIMATION OF PURITY OF GLYCEROL

BY DICHROMATE METHOD AIM To estimate the percentage purity of the given sample of Glycerol by Dichromate method. THEORY

Glycerol can be quantitatively oxidized by the known excess of acidified K2Cr2O7 into

Carbon dioxide and water:

K2Cr2 O7 + 4 H2SO4 → K2SO4 + Cr2 (SO4)3 + 3 (O) + 4 H2O

C3 H8 O3 + 10 (O) → 3 CO2 + 4 H2O

The amount of dichromate consumed by glycerol can be determined by refluxing glycerol

with a known excess of Potassium dichromate solution and then titrating the unreacted

dichromate against std. Sodium thio sulphate solution using starch indicator.

APPARATUS REQUIRED Burette, Pipette, Conical flask, Iodine flask and water bath. CHEMICALS REQUIRED Glycerol (standard and sample), 10% KI solution, starch, dil. H2SO4 , Sodium thiosulphate and Potassium dichromate solutions. PROCEDURE I. Standardization of Sodium thiosulphate:

1) Titrate 20 ml of std. Potassium dichromate solution + 20 ml of dil. H2SO4 + 10 ml of

10% KI solution against Sodium thiosulphate solution.

2) When the solution turns pale yellow, add 1 ml of freshly prepared starch solution and

continue the titration. End point is change of colour from blue to green.

3) Repeat the above procedure for concordant values.

II. Estimation of Glycerol:

1) Pipette out 10 ml of the given sample of glycerol solution into a clean iodine flask. Add 60

ml of 0.1 N K2Cr2 O7 and 1 test tube of dil. H2SO4.

2) Heat the contents of iodine flask on a water bath for 60 min and cool.

3) Add 1 test tube of dil. H2SO4 and 10 ml of 10 % KI solution to the above solution.

4) Titrate the liberated iodine against std. Sodium thiosulphate solution using starch

indicator. End point is the colour change from blue to green.

5) Repeat this procedure with pure standard Glycerol.

Page 17: Chemical Analysis Lab Manual

RESULT The percentage purity of the given sample of Glycerol was found to be _________%. OBSERVATIONS & CALCULATIONS Titration I: Standardization of Sodium thiosulphate solution

Burette solution : Sodium thio sulphate solution

Pipette solution : Standard K2Cr2O7 solution

Additional solution : 10 ml of H2SO4 + 10 ml of 10% KI

Indicator : Starch

End point : Blue to green

Burette Reading (ml) S.NO Volume Of

K2Cr2O7 Solution

(V1) ml

Initial Final Volume Of Sodium Thio Sulphate Solution

(ml)

Concordant Value (ml)

1

2

Volume of K2Cr2O7 (V1) =

Normality of K2Cr2O7 (N1) =

Volume of Na2S2O3 (V2) =

Normality of Na2S2O3 (N2) = (V1xN1) / V2

Titration II: Estimation of Glycerol:

Burette solution : Standard Sodium Thiosulphate solution

Solution in Iodine flask : 10 ml of Glycerol sample + 60 ml of K2Cr2O7 + 1 test tube of

H2SO4 +10 ml of 10%KI

Indicator : Starch

End point : Blue to Green

Page 18: Chemical Analysis Lab Manual

A. Estimation of Sample Glycerol:

Burette Reading (ml) S.NO Volume Of

Glycerol Solution

(V3) ml

Initial Final Volume Of Sodium Thio Sulphate

Solution (V4)ml

Concordant Value (ml)

1

2

B. Estimation of Standard Glycerol:

Burette Reading (ml) S.NO Volume Of

Glycerol Solution

(V3) ml

Initial Final Volume Of Sodium Thio Sulphate

Solution (V5)ml

Concordant Value (ml)

1

2

sampleVN

NVGlycerolsamplewithOCrKunreactedofVolume =

×=

1

24722

stdVN

NVGlyceroldaredswithOCrKunreactedofVolume =

×=

1

25722 tan

Volume of reacted 722 OCrK = 722 OCrK volume taken initially – volume of unreacted 722 OCrK

= 60 - volume of unreacted 722 OCrK

Glycerol ofmg 10152.01 722 =OCrKNofml

( )mgwsolutionsampletheinGlycerolofAmount

NmlVsample

sample ===××−

10152.0

60 1

( )mgwsolutiondardstheinGlycerolofAmount

NmlVstd

std ===××−

tan10152.0

60 1

100×=std

sample

w

w

mlVdichromateunreactedtoingcorrespondtethiosulphaofVolume 4=

100tan

×=Glyceroldardsofweight

GlycerolsampleofweightGlycerolofpurityPercentage

Page 19: Chemical Analysis Lab Manual

11. PROXIMATE ANALYSIS OF COAL

Aim: To assess the quality of coal by proximate analysis. Apparatus and Equipment Required: Hot air oven, Muffle Furnace, Crucible, Desiccator and sample of coal. Procedure:

i) Moisture: About 1 gram of finely powdered air dried coal sample was weighed in a

crucible was placed inside an electric hot air oven maintained at 105 -1100C. The crucible was

allowed to remain in the oven for 1 hour and taken out with a pair of tones cooled in a

desiccator and weighed. Loss in weight was reported as moisture.

100×

=

takencoalofWeightWeightofLoss

Moisture%

ii) Volatile Matter: The dried sample of coal left in the crucible was covered with a lid

and placed in an electric furnace maintained at C050925± the crucible was taken

out of the oven after 7 minutes of heating. The crucible was cooled first in air and

then in a desiccator and weighed. Loss in weight was reported as volatile matter on

percentage basis.

100×

=

takencoalofWeightmattervolatileofremovaltodueweightinLoss

MatterVolatile%

iii) Ash: The residual coal was then heated in a muffle furnace at 500C for half an hour.

The crucible was taken out and cooled first in air and desiccator and then weighed.

Heating, cooling and weighing was repeated till constant weight was obtained. The

residue was reported as ash on percentage basis.

100×

=

takencoalofWeighttakenashofWeight

Ash%

( )MatterVolatileAshMositureofCarbonFixed %%%100 ++−=

Result: S.No Proximate Analysis of Percentage 1. Moisture 2 Volatile Matter 3 Ash 4 Fixed Carbon

Page 20: Chemical Analysis Lab Manual

Calculation: Weight of coal taken = g Weight of crucible = g Wt. of coal + crucible = g After heating to 1050C (Oven) = g

100×

=

takencoalofWeightWeightofLoss

Moisture%)i

After heating Muffle Furnace 9250C

100×

=

takencoalofWeightmattervolatileofremovaltodueweightinLoss

MatterVolatile%)ii

Heating half an hour in muffle furnace 500C

100×

=

takencoalofWeighttakenashofWeight

Ash%)iii

( )MatterVolatile%Ash%Mositureof%CarbonFixedof% ++−= 100

Page 21: Chemical Analysis Lab Manual

12. FLASH AND FIRE POINT

Aim: To determine flash and fire point for the given sample. Apparatus Required: Pensky Martens closed flash tester, thermometer and sample. Procedure:

i) All parts of the cup were cleaned and dried before starting the test.

ii) The cup was filled with sample to be tested to the level indicated by filling mark.

iii) The lid was placed on the cup and thermometer was inserted.

iv) The material to be tested and tester was brought to a temperature of C0515± , lower than

the estimated flash point.

v) The heat was supplied at such a rate that the temperature in thermometer increased.

vi) The stirrer was turned at low flow rates such that the stirrer was directed in the downward

direction.

vii) The observed flash point was recorded such that the temperature on thermometer at the

time of test flame application caused a distinct flash in the interior of the cup.

viii) The temperature was increased till fuel burned for 5 second. The fire point temperature

was noted.

Result: The flash and fire point for the given sample was found to be ____0C and ________

0C

respectively. Tabular Column:

Sample Flash Point (0C) Fire Point (0C)

Page 22: Chemical Analysis Lab Manual

DEPARTMENT OF CHEMICAL ENGINEERING

LAB MANUAL

CH 2257 - CHEMICAL ANALYSIS LAB

INDEX S.NO NAME OF THE EXPERIMENT PAGE NO REMARKS

1 Estimation of Acid value ( Analysis of Oil) 1

2 Estimation of Saponification value(Analysis of Oil) 3

3 Estimation of Iodine value (Analysis of Oil) 5

4 Estimation of Silica content (Analysis of Cement) 8

5 Estimation of Mixed oxide content(Analysis of Cement) 9

6 Estimation of Calcium oxide content(Analysis of Cement) 10

7 Estimation of Total fatty matter content 11

8 Estimation of Total alkali content 12

9 Estimation of Residual chlorine in water 13

10 Estimation of Purity of Glycerol 16

11 Estimate the Proximate analysis of the given sample of coal 19

12 Determine the Flash and Fire point for the given samples 21

Prepared by Reviewed by Approved by CH2257 CHEMICAL ANALYSIS LAB 0 0 3 2 OBJECTIVE

Page 23: Chemical Analysis Lab Manual

To learn basic principles involved in estimation and characterization of industrially important materials. I. Soap Analysis a. Estimation of total fatty acid. b. Estimation of percentage alkali content. II. Oil Analysis

a. Estimation of free acid b. Determination of Saponification value c. Determination of iodine value

III. Cement Analysis

a. Estimation of Silica content b. Estimation of mixed oxide content c. Estimation calcium oxide content d. Estimation of calcium oxide by rapid method

IV. Coal Analysis

a. Estimation of Sulphur present in coal b. Ultimate analysis of coal c. Proximate analysis of coal

V. Analysis of Bleaching Power a. Estimation of Available Chlorine VI. Analysis of Glycerol

a. Estimation of purity of glycerol VII. Analysis of fuels

a. Flash point b. Fire point c. Cloud point d. Pour point e. Aniline point

TOTAL : 45 PERIODS

REFERENCES 1. Technical Analysis Manual, Chemistry Division, Chemical Engineering Department, A.C.

Tech. Anna University (2007). 2. Hand book of Chemical Analysis by Griffin.

Page 24: Chemical Analysis Lab Manual

SSN COLLEGE OF ENGINEERING

SSN NAGAR, KALAVAKKAM – 603 110.

DEPARTMENT OF CHEMICAL ENGINEERING

CHEMICAL ANALYSIS

LAB MANUAL