Expchemmanulwith Readings

Applied Chemistry Lab Manual

(I B.Tech Civil Engineering )

Experiment-1 ESTIMATION OF FERROUS IRON (Redox Titrations) Aim: To estimate the amount of Ferrous iron in the whole of the given solution using a standard solution of Potassium Dichromate. Apparatus:

100 ml standard flask, Burette, 250 ml Conical Flask, 20 ml Pipette, Funnel & Simple balance with Fractional weights.

Chemicals Required: Potassium dichromate (K2Cr2O7) Sulphuric acid (H2SO4) Syrupy phosphoric acid (H3PO4) Diphenylamine Ferrous iron solution & distilled water. Principle: Ferrous Iron is oxidized to Ferric iron by Potassium Dichromate in acid solution. The completion of oxidation reaction is marked by the appearance of Blue violet color of Diphenylamine, which is used as an internal indicator. Chemical reactions: K2Cr2O7 + 4H2SO4  K2SO4 + Cr2(SO4)3 + 4H2 + 3(O) 2FeSO4 + H2SO4 + (O)  Fe2(SO4)3 + H2O K2Cr2O7 = 3(O) = 6Fe Procedure: 1. Preparation of standard potassium dichromate: Weigh out accurately the given pure crystalline sample of potassium dichromate and transfer into 100 ml standard (volumetric) flask provided with a funnel. Dissolve the dichromate in a small quantity of distilled water, and make upto the mark. The contents in the flask are shaken well for uniform concentration. Calculate the normality of potassium dichromate. 2. Estimation of Iron: Make up given solution upto the mark with distilled water and shake the flask for uniform concentration. Rinse the pipette with the ferrous solution and pipette out 20ml into a clean conical flask add 20ml of the acid mixture (sulphuric acid and phosphoric acid), and four to five drop of diphenylamine indicator. Fill the burette with the prepared potassium dichromate solution after rinsing it, with the same. Titrate the solution in the conical flask against the standard potassium dichromate from the burette till the color changes to blue violet. Repeat the titrations for concurrent titre values. Result: Amount of Ferrous iron present in the whole of the given solution (100 ml) = 0.558 gm _______________________________________________________________________________ Guru Nanak Engineering College Complied by B.srinivas 1

Applied Chemistry Lab Manual (I B.Tech Civil Engineering ) Preparation of Standard (K2Cr2O7) solution: W1 = Weight of bottle + substance(K2Cr2O7) = ____12.500________ gms W2 = Weight of bottle

= ___12.010_________ gms

Weight of substance (K2Cr2O7) = (W1-W2) = ___0.490_________ gms. Normality of the K2Cr2O7solution = (W1-W2) X 10 Equivalent Weight N= S.No Volume of standard solution (V2) 1

(W1-W2) X 10 = .490X10 49 49 Burette Reading

= 0.1 N

Volume of consume (V1)

Initial 0

Final 20

20

40

20

0

20

20

20

20 ml

2

20 ml

3

20 ml V2 = 20 ml

V1 = 20

Calculation: N1 = Normality of K2Cr2O7 solution = 0.1 N N2 = Normality of Ferrous iron solution = ? V1 = Volume of K2Cr2O7 solution = 20 ml V2 = Volume of Ferrous iron solution = 20 ml N1 V1= N2 V2 N2 = N1 V1 V2 Normality of Ferrous iron solution = N2 = N1 V1 = 0.1 X 20 = 0.1 N V2 20 Amount of Ferrous iron present in the whole of the given solution (100 ml) = N2 X 55.85 10 = 0.1 X 55.85 10 Result: Amount of Ferrous iron present in the whole of the given solution (100 ml) = .558 gm. _______________________________________________________________________________ Guru Nanak Engineering College Complied by B.srinivas 2

Applied Chemistry Lab Manual

(I B.Tech Civil Engineering )

Experiment-2 ESTIMATION OF FERRIC IRON (Redox Titrations) Aim: To estimate the amount of Ferric iron in the whole of the given solution using a standard solution of Potassium Dichromate. Apparatus: 100 ml standard flask, Burette, Conical Flask, 20 ml Pipette, Simple balance with weights, Chemicals Required: K2Cr2O7, SnCl2, HgCl2, HCl, Ferric ion solution, H2SO4, Ortho phosphoric acid, Diphenylamine & distilled water. Principle: Ferric Iron is reduced to ferrous iron by stannous chloride in the present of Hydrochloric acid at a temperature of 70-900C. The excess stannous chloride is removed by the addition of mercuric chloride. The ferrous iron formed is titrated with standard Potassium dichromate solution in the presence of Sulphuric acid and Phosphoric acid using diphenylamine as indicator. Chemical reactions: 2FeCl3 + SnCl2  2FeCl2 + SnCl4 SnCl2 + 2HgCl2  SnCl4 + Hg2Cl2 K2Cr2O7 + 4H2SO4  K2SO4 + Cr2(SO4)3 + 4H2O + 3(O) 2FeSO4 + H2SO4 + (O)  Fe2(SO4)3 + H2O K2Cr2O7 = 3(O) = 6Fe Procedure: 1. Preparation of standard potassium dichromate: Weigh out accurately the given pure crystalline sample of potassium dichromate and transfer into 100 ml standard (volumetric) flask provided with a funnel. Dissolve the dichromate in a small quantity of distilled water, and make upto the mark. The contents in the flask are shaken well for uniform concentration. Calculate the normality of potassium dichromate. 2. Estimation of ferric iron: Make up the given ferric iron solution upto the mark of the 100ml standard flask with distilled water and shake well for uniform concentration. Pipette out 20ml of the ferric solution into a clean conical flask and 10ml of conc. HCl and heat the solution to boiling. The colour of the solution changes to clear yellow. Add stannous chloride solution drop by drop into the hot iron solution from a burette till the yellow colour disappears. Cool the solution under a tap and add 10 ml of saturated solution of mercuric chloride in one portion silky white precipitate of mercurous chloride is obtained, (if the solution turns black, due to formation of finely divided mercury, discard the solution and take fresh solution of ferric iron and reduce) add 20 ml of the acid mixture and 3 to 4 drops of diphenylamine indicator and titrate against standard solution of potassium dichromate till the green colour changes to blue violet. Repeat the titration for concurrent value and calculate the normality of iron solution. Result: Amount of Ferric iron present in the whole of the given solution (100 ml) = 0.558 gm. _______________________________________________________________________________ Guru Nanak Engineering College Complied by B.srinivas 3

Applied Chemistry Lab Manual (I B.Tech Civil Engineering ) Preparation of Standard (K2Cr2O7) solution: W1 = Weight of bottle + substance(K2Cr2O7) = ____12.500________ gms W2 = Weight of bottle

= ___12.010_________ gms

Weight of substance (K2Cr2O7) = (W1-W2) = ___0.490_________ gms. Normality of the K2Cr2O7solution = (W1-W2) X 10 Equivalent Weight N= S.No Volume of standard solution (V2) 1

(W1-W2) X 10 = .490X10 49 49 Burette Reading

= 0.1 N

Volume of consume (V1)

Initial 0

Final 20

20

40

20

0

20

20

20

20 ml

2

20 ml

3

20 ml V2 = 20 ml

V1 = 20

Calculation: N1 = Normality of K2Cr2O7 solution = 0.1 N N2 = Normality of Ferric iron solution = ? V1 = Volume of K2Cr2O7 solution = 20 ml V2 = Volume of Ferric iron solution = 20 ml N1 V1= N2 V2 N2 = N1 V1 V2 Normality of Ferric iron solution = N2 = N1 V1 = 0.1 X 20 = 0.1 N V2 20 Amount of Ferric iron present in the whole of the given solution (100 ml) = N2 X 55.85 10 = 0.1 X 55.85 10 Result: Amount of Ferric iron present in the whole of the given solution (100 ml) = .558 gm. _______________________________________________________________________________ Guru Nanak Engineering College Complied by B.srinivas 4

Applied Chemistry Lab Manual

(I B.Tech Civil Engineering ) Experiment-3 ESTIMATION OF COPPER (IODOMETRY)

Aim: To estimate the amount of Copper present in the given solution using a standard solution of Potassium Dichromate and Hypo as the link solution. Apparatus: 100 ml standard flask, Funnel, Burette, Iodometric flask, Conical Flask, Pipette, Simple balance with weights, Chemicals Required: K2Cr2O7, Hypo (Na2S2O3), KI, Conc.HCl, dil. Acetic acid, NaHCO3, H2SO4, CuSO4, Ammonia solution, Starch & distilled water. Principle: Any cupric salt in neutral medium when treated with Potassium Iodide forms a white precipitate of cuprous iodide and iodine is set free quantitatively. The liberated Iodine is treated against Hypo using starch as the indicator. Chemical reactions: CuSO4 + 2KI  CuI2 + K2 SO4 2CuI2  Cu2I2 + I2 I2 + 2Na2S2O3 + O2  Na2S2O6 + 2NaI 2CuSO4 = I2 = Na2S2O3 Procedure: 1. Preparation of standard potassium dichromate: Weigh out accurately the given pure crystalline sample of potassium dichromate and transfer into 100 ml standard (volumetric) flask provided with a funnel. Dissolve the dichromate in a small quantity of distilled water, and make upto the mark. The contents in the flask are shaken well for uniform concentration. Calculate the normality of potassium dichromate. 2. Standardization of sodium thiosulphate: Rinse the burette and fill it up with hypo solution without any air bubbles. Note the burette reading. Take about 20 ml of 10%KI solution in a clean conical flask and add 2 grams of sodium bicarbonate followed by 5 ml of concentrate HCl gently rotate the flask for mixing the liquids. Rinse the pipette with a little of potassium dichromate solution and then transfer 20 ml of the same to the conical flask. Shake it well, stopper it, and keep it in dark place for 5 minutes. Titrate the liberate iodine by running down hypo from the burette with constant stirring. When the solution attains a pale yellow colour add 2 ml of freshly prepared starch solution. The colour changes to blue. Continue the titration drop-wise till the colour changes from blue to light green indicating the end point. Repeat the titration for concurrent values. 3. Estimation of copper: Make up the given solution of copper to 100 ml with distilled water and shake well for uniform concentration. Pipette out 20 ml of this solution into a clean conical flask. Add few drops of ammonia when bluish white precipitate is obtained. Redissolve the precipitate in dilute acetic acid. Now add 10 ml of 5% KI, when iodine is liberated giving a brown colour. Titrate this solution against standard hypo solution till light yellow colour is obtained. Now add 2 ml of starch solution and continue the titration till blue colour changes to creamy white, which is the end point. Repeat the titration for concurrent values and calculate the amount of copper. _______________________________________________________________________________ Guru Nanak Engineering College Complied by B.srinivas 5

Applied Chemistry Lab Manual Preparation of Standard solution: W1 = Weight of bottle + substance = __12.500___ gms W2 = Weight of bottle = __12.010___ gms Weight of substance = (W1-W2) = ___0.490____ gms.

(I B.Tech Civil Engineering )

Normality of the solution = (W1-W2) X 10__ = (W1-W2) X 10 Equivalent Weight 49 S.No Volume of standard (K2Cr2O7)solution (V1) 1 2

20 ml 20 ml

Burette Reading Initial 0 20

Final 20 40

3

20 ml 0 20 V1 = 20 N1 = Normality of Potassium dichromate = 0.1 N V1 = volume of Potassium dichromate = 20 ml N2 = Normality of Hypo =? V2 = Volume of Hypo = 20 N1V1 = N2V2 N2 = N1V1 = 0.1 X 20 = 0.1 N V2 20 N2 = Normality of Hypo = 0.1 N

S.No Volume of Copper solution (V3) 1

20 ml

2

20 ml

3

20 ml V3 = 20 ml

Burette Reading

= 0.490 X 10 = 0.1 N 49

Volume of consume (V2) 20 20 20 V2 = 20

Volume of consume (V4)

Initial 0

Final 19

19

38

19

0

19

19

19

V4 = 19

N3= Normality of Copper solution = ? V3 = volume of Copper Solution = 20 ml N4 = Normality of Hypo = 0.1 N V4 = Volume of Hypo = 19 N3V3 = N4V4 Normality of Copper solution = N3= N4V4 = 0.1 X 19 = 0.095 N V3 20 Amount of Copper present in the whole of the given solution = N3 X 63.54 = 0.095X63.54 = 0.603 10 10 Result: Amount of Copper present in the whole of the given solution (100 ml) = 0.603 gm. Experiment-4 _______________________________________________________________________________ Guru Nanak Engineering College Complied by B.srinivas 6

Applied Chemistry Lab Manual (I B.Tech Civil Engineering ) ESTIMATION OF CALCIUM HARDNESS OF WATER (COMPLEXOMETRY) Aim: To estimate the Calcium hardness of the given solution using a standard solution of EDTA. Apparatus: 100 ml standard flask, Burette, 250 ml Conical Flask, 20 ml Pipette & Simple balance with weights, Chemicals Required: Ethylene di-amine tetra acetic acid (EDTA), Solochrome (EBT) Indicator, Ammonia Buffer solution, Hard-water & distilled water. Principle: Hard water which contains calcium and magnesium ions forms a wine red colored complex with the indicator, Eriochrome Black-T. Ethylene diamine tetra acetic acid (EDTA) forms a colourless stable complex with free metal ion like Ca, Mg. i.e., Metal + Indicator  Metal indicator complex (wine red colour) When EDTA is added from the burette, it extracts the metal ions from the metal ion-indicator complex thereby releasing the free indicator. (The stability of metal ion-indicator complex is less than that of the metal ion- EDTA complex, and hence EDTA extracts metal ion form the ionindicator complex.) EDTA + Metal indicator complex  Metal ion-EDTA + Indicator (wine red colour) (Blue) The reactions take place at a pH = 10 and the buffer is made by ammonium chloride and ammonium solution. Procedure: 1. Preparation of standard solution of EDTA: Weigh out accurately about 0.03722 gms of EDTA sample into a 100ml standard flask and dissolve in a minimum quantity of distilled water. Make up the solution upto the mark with distilled water and shake the flask well for uniform concentration. M1 = Molarity of the EDTA solution = Weight of EDTA transferred x 10 372.24 2. Estimation of Calcium hardness of water: Make up the given solution of calcium upto the mark and shake the flask well for uniform concentration. Rinse the pipette with the calcium solution and pipette out 20 ml into a clean conical flask. Add 2 ml of buffer followed by 1-2 ml of Eriochrome Black – T and titrate the solution till a clear blue colour persists. This marks the end point of the titration. Repeat the titrations for constant titer values and calculate the amount of calcium present in the whole of the given solution. Result: The calcium hardness of the given water sample = _250__ ppm. Preparation of Standard solution: _______________________________________________________________________________ Guru Nanak Engineering College Complied by B.srinivas 7

Applied Chemistry Lab Manual

(I B.Tech Civil Engineering )

W1 = Weight of bottle + substance = 12.500 gms W2 = Weight of bottle

= 12.130 gms

Weight of substance = (W1-W2) = 0.370 gms. Molarity of the solution = (W1-W2) X 10 = 0.370 X 10 = 0.01 M 372.24 372.24 S.No Volume of standard solution (V2) 1

Burette Reading

Volume of consume (V1)

Initial

Final

0

5

5

5

10

5

10

15

5

20 ml

2

20 ml

3

20 ml V2 = 20 ml

V1 = 5

Calculations: M1 = Molarity of EDTA = 0.01 M V1 = volume of EDTA solution = 5 M2 = Molarity of calium solution = ? V2 = Volume of Calcium solution = 20 ml M1V1 = M2V2 M2 = Molarity of calium solution = M1V1 = 0.01 X 5 = 0.0025 V2 20 Calcium hardness of the given sample water = M2 X 100 X 1000 = 0.0025 X 100 X 1000 = 250

Calcium hardness of the given sample water = M2 X V1 X100 X 1000 V2 = 0.01 X 5X100 X 1000 = 250 ppm 20 Result: The calcium hardness of the given water sample ___250______ ppm. Experiment-5 _______________________________________________________________________________ Guru Nanak Engineering College Complied by B.srinivas 8

Applied Chemistry Lab Manual (I B.Tech Civil Engineering ) ESTIMATION OF COPPER BY EDTA (COMPLEXOMETRY) Aim: To estimate the Copper in the given solution by preparing a standard solution of EDTA. Apparatus: 100 ml standard flask, Burette, 250 ml Conical Flask, 20 ml Pipette, Simple balance with weights, Chemicals Required: Ethylene di-amine tetra acetic acid (EDTA), Fast sulphone Black-F Indicator, Ammonia solution, Copper solution, Distilled water. Principle: Fast sulphone Black-F indicator is specific in its reaction with copper in ammonia solution, it forms red complex with copper. In the titration of copper in ammonical solution the colour changes at the end point from pale blue to bright green depend upon the concentration of Cu++ ions. Procedure: 1. Preparation of standard solution of EDTA: Weigh out accurately about 0.3722 gms of EDTA sample into a 100ml standard flask and dissolve in a minimum quantity of distilled water. Make up the solution upto the mark with distilled water and shake the flask well for uniform concentration. 2. Estimation of Copper: Makeup the given solution of copper upto the mark and shake the flask well for uniform concentration. Rinse the pipette with the copper solution and pipette out 20 ml of copper solution into a clean 250 ml conical flask. Add 20 ml of distilled water and 5 ml of ammonia solution and 5 drops of the fast sulphone black-F indicator solutions titrate with standard EDTA solution until the colour changes of from blue to a dark green. Repeat the titration to get the concurrent values.

Result: Amount of copper present in the given 100ml of solution = 635 mg

Preparation of Standard solution: _______________________________________________________________________________ Guru Nanak Engineering College Complied by B.srinivas 9

Applied Chemistry Lab Manual W1 = Weight of bottle + substance = _____12.500__ gms W2 = Weight of bottle

(I B.Tech Civil Engineering )

= ___12.130___ gms

Weight of substance = (W1-W2) = ____0.370___ gms. Molarity of the solution = (W1-W2) X 10 Molecular Weight S.No Volume of standard solution (V2) 1

20 ml

2

20 ml

3

20 ml

Burette Reading

= 0.370 X 10 = 0.01 M 372.24 Volume of consume (V1)

Initial

Final

0

20

20

20

40

20

0

20

20

V2 = 20 ml

V1 = 20

Calculation: M1 = Molarity of EDTA = 0.01 V1 = volume of EDTA solution = 20 M2 = Molarity of copper solution = ? V2 = Volume of Copper solution = 20 ml M1V1 = M2V2 M2 = Molarity of copper solution = M1V1 = 0.01 X 20 = 0.01M V2 20 1 ml of 0.05 M EDTA = 3.177 mg of Cu2+ Amount of copper present in the given 100ml of solution = Titre value x Molarity of EDTA x 3.177 x 1000 0.05 x 20 = 20 X 0.01 X 3.177 X 1000 = 635 mg 0.05 X 20 Result: Amount of copper present in the given 100ml of solution = 635 mg Experiment-6 ESTIMATION OF FERROCYANIDE _______________________________________________________________________________ Guru Nanak Engineering College Complied by B.srinivas 10

Applied Chemistry Lab Manual (I B.Tech Civil Engineering ) (PRECIPITATION TITRATIONS) Aim: To estimate the amount of Potassium Ferrocyanide in the given solution by preparing a standard solution of Zinc. Apparatus: 100 ml standard flask, Burette, 250 ml Conical Flask, 20 ml Pipette, 20 ml Measuring cylinder, Simple balance with weights. Chemicals Required: Zinc oxide (ZnO), Sulphuric acid (H2SO4), Potassium Ferrocyanide, Ammonium sulphate (NH4)2SO4, Biphenyl benzidine indicator, Distilled water. Principle: Zinc ions in neutral or acid medium reacts with Potassium Ferrocyanide solution to form sparingly soluble potassium zinc Ferro cyanide. 3Zn2+ + 2K4 Fe(CN)6 K2Zn3 Fe(CN)6 + 6K+ Biphenyl benzidine is used as indicator. At the end point the colour of the solution changes from Blue violet to pale green. Procedure: 1. Preparation of Standard Zinc solution: Weigh out the given zinc oxide into a 100 ml standard flask, dissolve it in 10 ml of diluted sulphuric acid and make upto the mark with distilled water and shake the flask well for uniform concentration. 2. Standardisation of Potassium Ferrocyanide: Make up the given potassium Ferro-cynide solution with distilled water and shake the flask well for uniform concentration. Rinse the pipette zinc oxide solution and pipette out 20 ml of zinc solution into 250 ml conical flask; add 20 ml of distilled water, 20 ml of 7N H2SO4, and 8 grams of ammonium sulphate and 3-4 drops of diphenyl benzidine indicator. Titrate the solution slowly, with vigorous shaking against potassium ferro-cynide until the colour changes from blue violet to green. Repeat the titration to get concurrent values. Result: Amount of Potassium Ferro-cyanide in the given solution = 0.283 gm

Preparation of Standard solution: W1 = Weight of bottle + substance = ___12.900___ gms _______________________________________________________________________________ Guru Nanak Engineering College Complied by B.srinivas 11

Applied Chemistry Lab Manual W2 = Weight of bottle

(I B.Tech Civil Engineering ) = ____12.090__ gms

Weight of substance = (W1-W2) = ____0.810____ gms. Molarity of the solution = (W1-W2) X 10 81.38

= 0.810 x 10 = 0.1 M 81.38

S.No Volume of standard solution (V1)

Burette Reading Initial

Final

1

20 ml

0 ml

20

20

2

20 ml

20

40

20

3

20 ml

0

20

20

V1 = 20 ml

Volume of consume (V2)

V2 = 20

M1 = Molarity of Zinc oxide solution = 0.1 M V1 = volume of Zinc oxide solution = 20 ml M2 = Molarity of Potassium ferrocyanide solution = ? V2 = Volume of Potassium ferrocyanide solution = 20 n1, n2 indicates number of molecules involved in the reaction n1= 3, n2= 2 Calculation: M2 = Molarity of Potassium ferrocyanide solution = M1V1 n2 V2 n1 M2 = M1V1 n2 = 0.1 X 20 X 2 V2 n1 20 X 3 M2 = 0.067 Amount of Potassium ferrocyanide in the given solution = M2X 422.4 = 0.067 X 422.4 = 0.283 g 100 100 Result: Amount of Potassium ferro-cyanide in the given solution = 0.283 g Experiment-7 DETERMINATION OF PERCENTAGE PURITY OF PYROLUSITE _______________________________________________________________________________ Guru Nanak Engineering College Complied by B.srinivas 12

Applied Chemistry Lab Manual (I B.Tech Civil Engineering ) (ANALYSIS OF MINERALS AND ORES) Aim: To estimate the amount of MnO2 present in the given sample and hence percentage purity of Pyrolusite. Apparatus: 100 ml standard flask, Burette, Conical Flask, 20 ml Pipette, Funnel, Simple balance with weights, Heating equipment. Chemicals Required: Pyrolusite, 4N Sulphuric acid (H2SO4), Sodium oxalate solution, Potassium permanganate (KMnO4), Distilled water. Principle: The MnO2 present in the pyrolusite sample is reduced by a known excess of standard sodium oxalate in acid medium. The unreacted sodium oxalate is titrated against a standard KMnO4, until pale pink coloured end point is obtained. MnO2 + H2SO4 + H2C2O4  2CO2 + 2H2O + MnSO4 Procedure: Weigh out accurately the given powdered pyrolusite sample into a clean dry conical flask and pipette out 40 ml of standard sodium oxalate solution and add 50 ml of 4N (H2SO4) sulphuric acid, put a small funnel into the mouth of the conical flask. Heat with small flame till particles are MnO2 disappear in the conical flask. Rinse the funnel with distilled water into the conical flask, titrate the hot solution, containing the unreacted sodium oxalate with standard KMnO4 solution till there is a pale pink colour.

Result: Percentage purity of the given sample of Pyrolusite = 76 %

Preparation of Standard solution:

_______________________________________________________________________________ Guru Nanak Engineering College Complied by B.srinivas 13

Applied Chemistry Lab Manual W1 = Weight of bottle + substance = __15.500____ gms W2 = Weight of bottle

(I B.Tech Civil Engineering )

= ____12.190___ gms

Weight of substance = (W1-W2) = ____3.10_____ gms. Normality of the solution = (W1-W2) X 10 = __3.10___X 10 = 1 N Equivalent Weight 31.6

S.No Volume of standard solution

Burette Reading

Volume of consume (V)

Initial

Final

1

20 ml

0

13

13

2

20 ml

0

13

13 V = 13

Calculations: Titer value = V = 13 Blank = 20 1 ml of 1N KMnO4 = 1N Na2C2O2 = 0.04346 g of MnO2 Percentage of MnO2 = (Blank-titervalue) X Normality of KMnO4 X 0.04346 X 100 Weight of the sample (gms) Percentage of MnO2 = 20-13 X 1 X 0.04346 X 100 = 76% 0.400 Note: Blank from the instructor i.e., 20 ml of oxalate equivalent to permanganate of certain normality.

Result: Percentage purity of the given sample of Pyrolusite = 76% Experiment-8 PERCENTAGE PURITY OF LIME-STONE _______________________________________________________________________________ Guru Nanak Engineering College Complied by B.srinivas 14

Applied Chemistry Lab Manual (I B.Tech Civil Engineering ) (ANALYSIS OF MINERALS AND ORES) Aim: To determine percentage purity of the sample of Lime stone (estimation of Calcium). Apparatus: 500 ml Beaker, Stirrer, 100 ml standard flask, Burette, 250 ml Conical Flask, Pipette, Funnel, Simple balance with weights, Heating equipment Distilled water & filter paper (No.40). Chemicals Required: Lime stone, Hydrochloric acid (HCl), Methyl red indicator, Sulphuric acid (H2SO4), 10% ammonium oxalate solution, Ammonium hydroxide, Potassium permanganate (KMnO4)& distilled water. Principle: The given Lime stone sample is weighed out into a beaker and dissolved in HCl. The calcium present in the solution is precipitated as oxalate by the addition of ammonium oxalate in neutal medium and the precipitate is dissolved in dilute H2SO4 and the liberate oxalic acid is titrated with standard KMnO4 solution. CaC2O4+H2SO4  CaSO4 + 3H2C2O4 5 (H2C2O4) + 2KMnO4  2MnSO4+ 10CO2 + 8H2O Procedure: Weigh out accurately the given Lime stone sample into a 400 ml beaker, add 10 ml of distilled water, then add 10 ml of dilute Hydrochloric acid along the sides of the beaker and completely dissolve the lime-stone sample. Add 4 to 5 drops of methyl red indicator, heat the solution to boiling add about 25 ml of 10% solution of ammonium oxalate solution with constant stirring. To the hot solution add 1:1 Ammonium hydroxide drop wise with stirring until the solution is neutral (Red to Yellow). Allow the solution to stand for 30 minutes on water bath. Test for complete precipitation and decant clear supernatant liquid through a Whatman No. 40 filter paper and quantitatively transfer the precipitate to the filter paper. Wash the precipitate on filter paper repeatedly until the washings are free from oxalate/chlorides. Transfer the precipitate present on the filter paper into a 400 ml beaker, add 25 to 30 ml dilute suphuric acid, warm the solution and titrate with standard permanganate solution to a pale pink colour end-point. Result: Amount of calcium present in the sample = 0.400 gm Percentage purity of the given sample of Limestone = 40 % Preparation of Standard solution: _______________________________________________________________________________ Guru Nanak Engineering College Complied by B.srinivas 15

Applied Chemistry Lab Manual W1 = Weight of bottle + substance = _12.600__ gms W2 = Weight of bottle

(I B.Tech Civil Engineering )

= __12.290__ gms

Weight of substance = (W1-W2) = __0.310__ gms. Normality of the solution = (W1-W2) X 10 = _0.310_X 10 = 0.1 N Equivalent Weight 31.6 S.No Volume of standard solution

Burette Reading

Volume of consume (V)

Initial

Final

1

20 ml

0

20

20

2

20 ml

20

40

20

3

20 ml

0

40

20 V = 20

Calculations: Titer value = V = 20 1 ml of KMnO4 = 0.200 g of Ca. Amount of calcium present in the sample = Titer value (V) X Normality KMnO4 X 0.2004 = = 20 X 0.1 X 0.2004 = 0.4008 gm % Purity of Lime stone = Amount of Calcium X 100 Weight of the sample = 0.400 X100 = 40% 1.000 Result: Amount of calcium present in the sample = 0.400 gm Percentage purity of the given sample of Limestone = 40 % Experiment-9 ESTIMATION OF MANGANESE IN STEEL _______________________________________________________________________________ Guru Nanak Engineering College Complied by B.srinivas 16

Applied Chemistry Lab Manual

(I B.Tech Civil Engineering ) (Colorimetric Estimation)

Aim: To estimate the percentage of Manganese present in a sample of mild steel calorimetrically. Apparatus: 100 ml standard flask, 250 ml Conical Flask, 20 ml Pipette, 10 ml Measuring cylinder, Funnel, Simple balance with weights, Heating equipment Colori-meter & centrifuge apparatus. Chemicals Required: Steel sample, Nitric acid (HNO3), Syrupy phosphoric acid(H3PO4), Lead peroxide & distilled water. Principle: The given steel sample is dissolved in nitric acid. Manganese (II) is oxidized to permanganic acid by heating with lead peroxide and conc. Nitric acid. The intensity of the permanganic acid is measured in the colorimeter and the amount of manganese is estimated. Procedure: 1. Dissolution of the steel sample: Weight out about 0.5 grams (500 mg) of the given steel sample into a clean 250 ml conical flask and add about 30 ml of 1:3 nitric acid heat to boiling, till the sample goes into solution. Boil gently for about 10 to 15 minutes, to oxidize any carbon present, cool and transfer into a clean 100 ml standard flask. Wash the conical flask twice with about 10 ml portions of distilled water and transfer into the standard flask. Make up the solution upto the mark with distilled water and shake well for uniform concentration. 2. Development of Colour: Transfer 20 ml of the prepared solution into a clean conical flask add about 10ml of syrupy phosphoric acid and about 20 ml of 1:3 nitric acid and heat the solution to boiling. Add two spatulas of lead peroxide and continue the boiling for about 5 minutes. Take out the flask from the stand and allow it to cool and settle. Decant the supernatant liquid into a 100 ml standard flask, wash the precipitate twice with little distilled water and collect the supernatant liquid and the washings into the standard flask and make up the solution with distilled water and shake well uniform concentration. Transfer about 10 ml of the solution into a clean centrifuge tube and centrifuge the solution to separate out any lead peroxide particles. Measure the optical density in the colorimeter and calculate the amount of Manganese from the standard calibration curve. Result: Percentage of Manganese present in the mild steel sample is = Weight of the sample:

_______________________________________________________________________________ Guru Nanak Engineering College Complied by B.srinivas 17

Applied Chemistry Lab Manual W1 = Weight of bottle + sample = _12.500____ gms W2 = Weight of bottle

(I B.Tech Civil Engineering )

= __12.000___ gms

Weight of sample = (W1-W2) = ____0.500______ gms. = ______500______ mgs Standard value for calibration curve Amount of Manganese (in mg)

O. D

0.1

0.035

0.2

0.065

0.3

0.100

0.4

0.130

0.5

0.155

0.6

0.190

0.7

0.220

0.8

0.245

0.9

0.260

X = Optical density of the solution = Y = Corresponding value of Mn from the curve = Calculations: Percentage of Manganese present in the steel sample = Y x 100 x 100 20 x (W1-W2) mg

Result: Percentage of Manganese present in the mild steel sample is =

Experiment-10 ESTIMATION OF FERRIC IRON IN CEMENT _______________________________________________________________________________ Guru Nanak Engineering College Complied by B.srinivas 18

Applied Chemistry Lab Manual

(I B.Tech Civil Engineering ) (Colorometric Estimation)

Aim: To estimate the amount of Iron (Ferric) present in a sample of cement by calorimetrically using ammonium thiocyanate as a reagent. Apparatus: 250 ml beaker, Glass rod, Watch glass, 100 ml standard flask, Burette, 10 ml Pipette, Simple balance with weights Colori-meter, Heating equipment. Chemicals Required: Cement sample, Conc. Nitric acid (HNO3), Hydrochloric acid (HCl) Ammonium thio-cyanate & Distilled-water. Principle: Ammonium thio-cyanate yields a blood red colour with ferric iron and the colour produced is stable in nitric acid medium. Its optical density is measured in a photo colorimeter and the concentration of ferric iron is found from a standard calibration curve. Procedure: 1. Dissolution of the sample: Weight out accurately about 0.1 gram of the cement sample into a clean 250 ml beaker add about 5 ml of water to moisten the sample. Place a glass rod and cover the beaker with a watch glass add about 5 ml conc. Hydrochloric acid (HCl) drop-wise and heat the solution till the sample dissolved. Keep the beaker on a small flame and evaporate the solution to almost dryness to expel the excess acid. 2. Development of Colour: pipette out 10 ml of the solution prepared above, into a 100 ml standard flask, add 1 ml of conc. Nitric acid (HNO3) from a burette and 5 ml of 40% ammonium thio-cyanate from a burette. Make up the solution to 100 ml with distilled water and shake the flask well for uniform concentration. Find out the optical density of the solution using the photo colorimeter and the concentration of the ferric iron from the calibration curve.

Result: Percentage of Ferric iron present in the cement sample =

Weight of the sample:

_______________________________________________________________________________ Guru Nanak Engineering College Complied by B.srinivas 19

Applied Chemistry Lab Manual

(I B.Tech Civil Engineering )

W1 = Weight of bottle + sample = _12.100_____ gms W2 = Weight of bottle

= ___12.000____ gms

Weight of sample = (W1-W2) = ___0.100_____ gms.

Standard value for calibration curve Concentration in Milligrams

O. D

0.05

0.11

0.10

0.22

0.15

0.32

0.20

0.40

0.25

0.50

0.30

0.62

0.35

0.70

0.40

0.80

X = corresponding amount of from the calibration curve = Calculation: Percentage of Fe3+ present in the given cement sample = X x 10 x 100 (W1 – W2) mg =

Result: Percentage of Ferric iron present in the cement sample =

ENGINEERING CHEMISTRY LAB I B.TECH CIVIL ENGINEERING _______________________________________________________________________________ Guru Nanak Engineering College Complied by B.srinivas 20

Applied Chemistry Lab Manual

(I B.Tech Civil Engineering )

Viva-voce questions Experiment-1 1. Define normality? 2. Define molarity? 3. How to prepare standard solution? 4. To explain the principle of this experiment. 5. To explain the difference between molarity & normality/ 6. Which indicator used in this experiment? 7. Which type of titration involved in this experiment? 8. Name the chemicals of in this experiment? 9. What is the molecular weight of potassium dichromate? 10. What is the molecular weight of ferrous ammonium sulphate? 11. Name the apparatus used this experiment?

Experiment-2 1. Define normality? 2. Define molarity? 3. How to prepare standard solution? 4. To explain the principle of this experiment. 5. To explain the difference between molarity & normality/ 6. Which indicator used in this experiment? 7. Which type of titration involved in this experiment? 8. Name the chemicals of in this experiment? 9. What is the molecular weight of potassium dichromate? 10. What is the molecular weight of ferric ammonium sulphate? 11. Name the apparatus used this experiment?

Experiment-3 1. Define normality? 2. Define molarity? 3. How to prepare standard solution? 4. To explain the principle of this experiment. 5. To explain the difference between molarity & normality/ 6. Which indicator used in this experiment? 7. What is the chemical formula of Hypo? 8. Which type of titration involved in this experiment? 9. Name the chemicals of in this experiment? 10. What is the molecular weight of potassium dichromate? 11. What is the molecular weight of Hypo? 12. Name the apparatus used this experiment?

Experiment-4 1. Define normality? _______________________________________________________________________________ Guru Nanak Engineering College Complied by B.srinivas 21

Applied Chemistry Lab Manual 2. Define molarity? 3. How to prepare standard solution? 4. To explain the principle of this experiment. 5. To explain the difference between molarity & normality/ 6. Which indicator used in this experiment? 7. Which type of titration involved in this experiment? 8. Name the chemicals of in this experiment? 9. What is the molecular weight of EDTA? 10. Name the apparatus used this experiment?

(I B.Tech Civil Engineering )

Experiment-5 1. Define normality? 2. Define molarity? 3. How to prepare standard solution? 4. To explain the principle of this experiment. 5. To explain the difference between molarity & normality/ 6. Which indicator used in this experiment? 7. Which type of titration involved in this experiment? 8. Name the chemicals of in this experiment? 9. What is the molecular weight of EDTA? 10. Name the apparatus used this experiment?

Experiment-6 1. Define normality? 2. Define molarity? 3. How to prepare standard solution? 4. To explain the principle of this experiment. 5. To explain the difference between molarity & normality/ 6. Which indicator used in this experiment? 7. Which type of titration involved in this experiment? 8. Name the chemicals of in this experiment? 9. What is the molecular weight of zinc oxide? 10. Name the apparatus used this experiment?

Experiment-7 1. Define normality? 2. Define molarity? 3. How to prepare standard solution? 4. To explain the principle of this experiment. 5. To explain the difference between molarity & normality/ 6. Which indicator used in this experiment? 7. In this experiment do-not required any indicator, why? 8. Name the chemicals of in this experiment? 9. 1 ml of 1N KMnO4 is equal to how much amount of MnO2? 10. What is the molecular weight of MnO2? 11. Name the apparatus used this experiment? _______________________________________________________________________________ Guru Nanak Engineering College Complied by B.srinivas 22

Applied Chemistry Lab Manual

(I B.Tech Civil Engineering )

Experiment-8 1. Define normality? 2. Define molarity? 3. How to prepare standard solution? 4. To explain the principle of this experiment. 5. To explain the difference between molarity & normality/ 6. Which indicator used in this experiment? 7. 1 ml of KMnO4 is equal to how many grams of calcium? 8. Name the chemicals of in this experiment? 9. What is the molecular weight of potassium permanganate? 10. Name the apparatus used this experiment?

Experiment-9 1. Define normality? 2. Define molarity? 3. Name the chemicals of in this experiment? 4. To explain the principle of this experiment. 5. To explain the difference between molarity & normality/ 6. Which indicator/reagent used in this experiment? 7. Which type of estimation involved in this experiment? 8. Define concentration of the solution? 9. Name the apparatus used this experiment?

Experiment-10 1. Define normality? 2. Define molarity 3. Name the chemicals of in this experiment? 4. To explain the principle of this experiment. 5. To explain the difference between molarity & normality/ 6. Which indicator/reagent used in this experiment? 7. Which type of estimation involved in this experiment? 8. Define concentration of the solution? 9. Name the apparatus used this experiment?

Experiment Chemicals Experiment-1 0.1N K2Cr2O7

Preparation 0.490 gm or 490 mg K2Cr2O7 makeup up to 100 ml with water

_______________________________________________________________________________ Guru Nanak Engineering College Complied by B.srinivas 23

Applied Chemistry Lab Manual H2SO4+ phosphoric acid Diphenylamine Ferrous iron solution Experiment-2 0.1N K2Cr2O7 Stannous Chloride

Experiment-3

Experiment-4

Experiment-5

Experiment-6

Experiment-7

Experiment-8

Experiment-9

Experiment10

Diphenylamine Ferric iron solution Mercuric chloride 0.1N K2Cr2O7 0.1N Hypo Starch Copper solution 10% KI 50% KI Acetic acid 0.01M EDTA Ammonia Buffer Solochrome/EBT Water/sample hard water 0.01M EDTA 0.01M CuSO4 NH3 Solution Fast sulphone black-F 0.1M ZnO 0.1M Pot. ferrocyanide Biphenyl benzidine Ammonium sulphate 7N H2SO4 MnO2 1 N KMnO4 0.1 N Na2C2O4 4N H2SO4 Lime stone, Hydrochloric acid (HCl), Methyl red indicator Dil. H2SO4 10% ammonium oxalate Ammonium hydroxide 0.1N KMnO4 Mild Steel sample Nitric acid (HNO3), phosphoric acid(H3PO4) Lead peroxide Cement sample, Conc. Nitric acid (HNO3) Hydrochloric acid (HCl)

(I B.Tech Civil Engineering ) 20 ml H2SO4+ 30 to 40 ml phosphoric acid makeup up to 100 ml with water 1 gm Diphenylamine in 10 to 20 ml conc.H2SO4 Mohr’s Salt (0.1N) 3.92 gm in 100 ml water 0.490 gm or 490 mg K2Cr2O7 makeup up to 100 ml with water 5.6 gm SnCl2 in 10 ml Conc. HCl allow it to stand until solution becomes clear then dilute up to 100 ml with water 1 gm Diphenylamine in 10 to 20 ml conc.H2SO4 FerricSalt (0.1N) 4.82 gm in 100 ml water 7 g Mercuric chloride in 100 ml water 0.490 gm or 490 mg K2Cr2O7 makeup up to 100 ml with water 2.48 gm Hypo in 100 ml with water 1g starch dissolve in 100 ml hot water 2.49 g CuSO4 in 100 ml water 10 g KI in 100 ml water 50 g KI in 100 ml water 28.5 or 30 ml Acetic acid + 70 ml water 0.370 g EDTA in 100 ml water 70 g NH4Cl + 570 ml NH3 + 430 ml water 0.4g or 400 mg EBT in 100 ml methanol 0.370 g EDTA in 100 ml water 0.249 g CuSO4 in 100 ml water 1g in 100 ml water/ alcohol 0.810 g ZnO in 100 ml water 0.422 g pot.ferrocyanide in 100 ml water 10 mg Biphenyl benzidine in 50 ml water/alcohol 8 g powder 19.4 or 20 ml H2SO4 + 80 ml water 400 mg MnO2 3.16 g KMnO4 in 100 ml water 0.670 g Na2C2O4 in 100 ml water 11.1 ml H2SO4 in 100 ml water 30 ml HCl + 70 ml Water 10 ml H2SO4 in 70 ml water 10 g Ammonium oxalate in 100 ml water 10 ml NH3 + 10 ml water 0.310 g KMnO4 in 100 ml water 500 mg Mild steel 10 ml Nitric acid + 30 ml water 100 mg cement

_______________________________________________________________________________ Guru Nanak Engineering College Complied by B.srinivas 24

Applied Chemistry Lab Manual Ammonium thio-cyanate

(I B.Tech Civil Engineering ) 40 gm Ammonium thio-cyanate in 100 ml water

_______________________________________________________________________________ Guru Nanak Engineering College Complied by B.srinivas 25