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Vellore – 632014,Tamil Nadu, India. www.vit.ac.in

MATERIALS & INSTRUMENTATION LABORATORY RECORD

FIRST YEAR B.TECH – Semester II

CHEMISTRY DIVISION

SCHOOL OF ADVANCED SCIENCES

VIT – A Place to learn; A chance to grow

Vellore – 632014,Tamil Nadu, India. www.vit.ac.in

VIT U N I V E R S I T Y (Estd. u/s u/s3 of U GC Act 1956)

Name : Batch : Reg. No :

VIT U N I V E R S I T Y (Estd. u/s u/s3 of U GC Act 1956)

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SCHOOL OF ADVANCED SCIENCES

First Year B.Tech – Semester – II

MATERIALS & INSTRUMENTATION LABORATORY

Reg. No Certified that this is a bonafide record of work done by………….. .………………………………………….. of ………………...………….…….. …………………….branch during the year …………………. at VIT University, Vellore – 632 014. This record is submitted for the Practical Examination held on:

Staff In-charge Signature of Signature of Internal Examiner External Examiner

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CONTENTS

S. No. TITLE

VOLUMETRIC ANALYSIS

1. Estimation of Copper in an alloy by Iodometry

2. Estimation of Nickel in an alloy by Complexometry

3. Estimation of Iron in an alloy by Cerimetry

4. Estimation of Zinc Using Potassium Ferrocyanide by Precipitation Method

INSTRUMENTAL ANALYSIS

5. Determination of concentration of a given sample using UV-Vis Spectrophotometer

6. Determination of concentration of alkali metal ions by flame photometry

7. Estimation of Sulphate ion by Turbidimetry

8. Preparation and Characterisation of Ruby by combustion method

9. Softening of Hard water by Zeolite Process

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INDEX

S. No.

Date

Name of the Experiment

Page No.

Result (10)

Faculty Sign.

1

2

3

4

5

6

7

8

9

CAT (30 M) = Signature of faculty VIVA (20 M) = Total (50 M) =

Date :

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1. ESTIMATION OF COPPER IN AN ALLOY BY IODOMETRY

Titration I: Standardisation of sodium thiosulphate

Burette reading (ml)

S. No.

Volume of Std CuSO4

(ml) Initial Final

Volume of Sodium

Thio Sulphate

(ml)

Calculation : Volume of Std CuSO4 = Normality of Std CuSO4 = Volume of Sodium Thio Sulphate = Normality of Sodium Thio Sulphate = ------------------N.

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1. ESTIMATION OF COPPER IN AN ALLOY BY IODOMETRY Exp. No: Date: Aim: To estimate the amount of copper present in the whole of the given solution. A standard solution of 0.01 N copper sulphate and an approximately 0.01N sodium thiosulphate solution are supplied. Principle: The experiment is based on the reaction between iodine and sodium thiosulphate. Copper sulphate liberate equal amount of iodine from KI solution in a weakly acidic medium as follows.

CuSO4 + 2KI CuI2 + K2SO4 2CuI2 Cu2I2 + I2

The liberated iodine is titrated against sodium thiosulphate using starch indicator until the blue colour disappears. Procedure: Titration I: Standardisation of Sodium thiosulphate Pipette out 20ml of standard copper sulphate solution into a clean conical flask. Add ammonium hydroxide drop by drop till a pale blue precipitate is formed. Dissolve the precipitate by adding a slight excess of dil. acetic acid. Then add 10ml of 10% KI solution and titrate the liberated iodine against sodium thiosulphate solution taken in the burette. When the solution turns straw yellow, add 1ml of freshly prepared starch as indicator and continue the titration. The end point is the disappearance of blue colour and appearance of dirty white solution. Repeat the titration for concordant value. Calculate the normality of sodium thiosulphate by using the normality of copper. Titration II: Estimation of Copper Transfer the given sample of copper solution into a clean 100ml standard flask and make up to mark using distilled water. Pipette out 20ml of made up copper solution into a clean conical flask. Add ammonium hydroxide drop by drop till a pale blue precipitate is formed. Dissolve the precipitate by adding a slight excess of acetic acid. Then add 10ml of 10% of KI solution and titrate the liberated iodine against standardised sodium thiosulphate solution taken in the burette. When the solution becomes straw yellow, add 1ml of freshly prepared starch as indicator and continue the titration. The end point is the disappearance of blue colour and appearance of dirty white solution. Repeat the titration for concordant value. Calculate the normality of copper solution by using the normality of sodium thiosulphate and estimate the amount of copper present in the whole of the given solution.

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Titration II : Estimation of Copper

Burette reading (ml)

S. No.

Volume of Unknown CuSO4

(ml) Initial Final

Volume of Sodium

Thio sulphate(ml)

Calculation : Volume of Sodium Thio Sulphate = Normality of Sodium Thio Sulphate = Volume of Unknown CuSO4 = Normality of Unknown CuSO4 = ----------------------N The amount of copper present in the whole of given solution = (Normality x Eq.Wt)/10 = ---------------------g.

Result: The amount of copper present in the whole of the given solution = g.

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2. ESTIMATION OF NICKEL IN AN ALLOY BY COMPLEXOMETRY

Titration I: Standardisation of EDTA

Burette reading (ml)

S. No.

Volume of Nickel Sulphate

(ml) Initial Final

Volume of

EDTA(ml)

Calculation : Volume of NiSO4 = Normality of NiSO4 = Volume of EDTA = Normality of EDTA =--------------------N.

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2. ESTIMATION OF NICKEL IN AN ALLOY BY COMPLEXOMETRY Exp. No: Date: Aim: To estimate the amount of Nickel present in the whole of the given nickel alloy solution. A standard solution of 0.01N Nickel sulphate and an approximately 0.01N EDTA solution are supplied. Principle: Nickel can be estimated by using EDTA as titrant and murexide as indicator. Murexide form complexes with nickel at pH 11. Murexide is the ammonium salt of Purpuric acid. The colour change in the direct titration of nickel at pH 10 – 11 is from yellow to bluish violet. Procedure: Titration I: Standardisation of EDTA Pipette out 20ml of standard nickel sulphate solution into a clean conical flask. Add a pinch of Murexide indicator and 10ml of 1M ammonium chloride solution and then add concentrated ammonia solution drop wise till the pH is about 7 as shown by yellow colour of the solution. Titrate the mixture in conical flask against EDTA taken in burette until colour changes from yellow to violet. (Nickel complexes rather slowly with EDTA and consequently the EDTA solution must be added drop wise very slowly near the end point). Repeat the titration to get concordant value. From the strength of Nickel sulphate solution calculate the strength of EDTA. Titration II: Estimation of Nickel Transfer the given nickel alloy solution into a clean 100ml standard flask quantitaively and make upto the mark using distilled water. Pipette out 20ml of made up nickel alloy solution into a clean conical flask. Add a pinch of Murexide indicator and 10ml of 1M ammonium chloride solution and then add concentrated ammonia solution drop wise till the pH is about 7 as shown by yellow colour of the solution. Titrate the mixture against standardised EDTA taken in burette until colour changes from yellow to violet. Repeat the titration to get concordant value. Calculate the strength of nickel solution by using strength of EDTA and hence the amount of nickel present in the given solution.

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Titration II: Estimation of Nickel

Burette reading (ml) S. No. Volume of Nickel Sulphate

(ml) Initial Final

Volume of

EDTA(ml)

Calculation Volume of EDTA = Normality of EDTA = Volume of NiSO4 = Normality of NiSO4 = -------------------N The amount of Nickel present in the whole of given solution = (Normality x Eq.Wt)/10 = ----------------------g.

Result: The amount of nickel present in the whole of the given solution = g.

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3. ESTIMATION OF FERROUS ION BY CERIMETRY

Titration I: Standardisation of Cerium (IV) sulphate solution:

Burette reading (ml)

S. No.

Volume of Std FeSO4

(ml) Initial Final

Volume of CAS

(ml)

Calculation : Volume of FeSO4 = Normality of FeSO4 = Volume of CAS = Normality of CAS =--------------------N.

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3. ESTIMATION OF FERROUS ION BY CERIMETRY

Exp. No: Date: Aim:

To estimate the amount of ferrous ion present in the whole of the given solution.A standard solution of 0.01N ferrous ammonium sulphate and an approximately 0.01N solution of Ceric ammonium sulphate are supplied. Principle: Ceric ions oxidise ferrous ions in acid medium according to the equation,

3324 ++++ +→+ FeCeFeCe

The ceric ammonium sulphate solution of approximately known strength is standardized against standard FAS. For the above titrations, redox indicator ferroin can be used. Ferroin is a complex formed between Fe(II) ion and 1,10-phenanthroline, [Fe(Phen)3]+2. The reduced form of indicator has an intense red colour, whereas oxidised iron (III) complex has a blue colour. The indicator reaction may be written as,

cPhenFe ++33 ])([ 2

3 ])([ +PhenFe

Pale blue Red When iron (II) is titrated with Ce (IV) in sulphuric acid medium, the ferroin indicator is initially red in colour in its reduced form.At the end point, Ce (IV) oxidises it to Fe (III) complex. The end point, is a sharp change from red to pale blue colour. Titration I: Standardisation of Cerium (IV) sulphate solution:

Pipette out 20ml of Ferrous ammonium sulphate solution in to a clean conical flask. Add about 20ml of 2N sulphuric acid followed by 2 drops of ferroin indicator. Titrate it against Cerium (IV) solution taken in the burette. The end point is colour change from red to pale blue colour. Repeat the titration to get concordant value. From the titre value, calculate the strength of cerium (IV) solution. Titration II: Estimation of Ferrous ion

Make up the given ferrous ion solution to 100ml in a standard flask. Pipette out 20ml of this solution in to a clean conical flask. Add about 20ml of 2N sulphuric acid solution and 2 drops of ferroin indicator. Titrate it against standardised cerium (IV) solution taken in the burette. End point is colour change from red to pale blue colour. Repeat the titration to get concordant value. From the titre value, calculate the strength of ferrous ion and hence calculate the amount of ferrous ion present in the given solution.

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Titration II: Estimation of Ferrous ion

Burette reading (ml)

S. No.

Volume of FeSO4

(ml) Initial Final

Volume of

CAS(ml)

Calculation Volume of CAS = Normality of CAS = Volume of FeSO4 = Normality of FeSO4 = --------------------N. The amount of Ferrous present in the whole of given solution =(Normality x Eq.Wt)/10 =----------------------g. Result: The amount of ferrous ion present in the whole of the given solution = ___________g.

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4. ESTIMATION OF ZINC USING POTASSIUM FERROCYANIDE BY PRECIPITATION

Titration I: Standardisation of Potassium ferrocyanide

Burette reading (ml) S. No. Volume of Zinc Sulphate

(ml) Initial Final

Volume of Potassium

ferrocyanide

(ml)

Calculation: Volume of ZnSO4 = Normality of ZnSO4 = Volume of Potassium ferrocyanide = Normality of Potassium ferrocyanide =--------------------N.

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4. ESTIMATION OF ZINC USING POTASSIUM FERROCYANIDE BY PRECIPITATION METHOD Exp. No: Date: Aim: To estimate the amount of zinc present in the whole of the given solution using potassium ferrocyanide by precipitation titration method. You are provided with a standard solution of 0.05 N zinc sulphate and an approximately 0.05 N potassium ferrocyanide solution. Principle: Zinc ions and ferrocyanide ions react in neutral or acid medium as follows

The zinc ions get precipitated as potassium zinc ferrocyanide.

The end point of the reaction can be detected using internal indicators such as diphenylamine, sodium diphenylamine sulphonate etc. These substances are oxidation – reduction indicators (redox indicators) whose action depends on the ratio of the concentration of ferricyanide in the solution. Thus in order to make the reaction an redox reaction, a small quantity of potassium ferricyanide is added to the ferrocyanide solution. When an excess of zinc ions are present in solution, the concentration of the ferrocyanide is very small and the reduction potential is large. When all the zinc ions are quantitatively precipitated, the next drop of ferrocyanide that is added in excess, will cause a sudden increase in [Fe(CN)6]2- and hence a sudden decrease in the potential. This results in the colour change of the redox indicator. The end point is colour change from blue to yellowish green. During titration, the solution should be thoroughly shaken, also the titration should be carried out very slowly especially near the end point. Procedure: Titration I: Standardisation of Potassium ferrocyanide Exactly 20 ml of standard zinc sulphate solution is pipette out in to a clean conical flask. Add 20 ml of 4 N sulphuric acid, and 2 to 4 drops of diphenylamine indicator. Titrate this mixture against potassium ferrocyanide taken in the burette. The end point is the colour change from blue to yellowish green. Repeat the titration for concordant titre value. From the titre value calculate the strength of potassium ferrocyanide

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Titration II: Estimation of Zinc

Burette reading (ml)

S. No.

Volume of Zinc Sulphate

(ml) Initial Final

Volume of Potassium

ferrocyanide

(ml)

Calculation Volume of Potassium ferrocyanide = Normality of Potassium ferrocyanide = Volume of ZnSO4 = Normality of ZnSO4 =--------------------N. The amount of Zinc present in the whole of given solution = (Normality x Eq.Wt)/10 =----------------------g.

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Titration II: Estimation of Zinc Transfer the given Zinc alloy solution into a clean 100ml standard flask quantitatively and make upto the mark using distilled water. Pipette out 20ml of made up solution in to a clean conical flask. Add 20ml of 4 N sulphuric acid, and 2 to 4 drops of diphenylamine indicator. Titrate this mixture against potassium ferrocyanide taken in the burette. The end point is the colour change from blue to yellowish green. Repeat the titration for concordant titre value. From the titre value calculate the strength of zinc solution and from the strength estimate the amount of zinc present in the whole of the given solution. Result:

The amount of Zinc present in the whole of the given solution = g.

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5. ESTIMATION OF IRON BY COLORIMETRY

Concentration Absorbance

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5. ESTIMATION OF IRON BY COLORIMETRY Exp. No: Date: Aim: To determine the amount of iron present in the given sample using colorimetry Principle: A complex of iron (II) is formed with 1,10-phenanthroline, Fe(C12H8N2)32+, and the absorbance of this colored solution is measured with a spectrophotometer. The spectrum is plotted to determine the absorption maximum. Hydroxylamine (as the hydrochloride salt to increase solubility) is added to reduce any Fe3+ to Fe2+ and to maintain it in that state. Solutions and chemicals required 1) Standard iron (II) solution - Prepare a standard iron solution by weighing 0.0176g of ferrous ammonium

sulfate, (Fe(NH4)2(SO4)2.6H2O). Quantitatively transfer the weighed sample to a 250ml volumetric flask and add sufficient water to dissolve the salt. Add 0.7ml con. Sulphuric acid, dilute exactly to the mark with distilled water and mix thoroughly. This solution contains 10mg iron per Liter (10ppm).

2) 1,10-phenanthroline solution - Dissolve 25mg of 1,10-phenanthroline monohydrate in 25ml water. Store in a plastic bottle.

3) Hydroxylamine hydrochloride solution - Dissolve 10g of hydroxylamine hydrochloride in 100ml water. 4) Sodium acetate solution - Dissolve 10g of sodium acetate in 100ml water. Procedure Into a series of 100ml volumetric flasks, add 1.00, 2.00, 5.00, 10.00 and 25.00 ml of the standard iron solution with pipettes. Into another 100ml volumetric flask, place 50ml distilled water for a blank. The unknown sample will be furnished in another 100ml volumetric flask. To each of the flasks (including the unknown) add 1.0ml of the hydroxylammonium chloride solution and 5.0mL of the 1,10-phenanthroline. The Iron (II)-phenanthroline complex forms at pH 2 to 9.Add 5ml of sodium acetate to neutralize the acid present and adjust the pH to a value at which complex forms.Dilute each solution to exactly 100ml. The standards will correspond to 0.1, 0.2, 0.5, 1 and 2.5 ppm of iron, respectively.Allow at least 15 minutes after adding the reagents before making absorbance measurements so that the color of the complex can fully develop. Once developed, the color is stable for hours. Obtain the absorption spectrum of 2.5-ppm solution by measuring the absorbance from about 400 to 700nm or the range of your instrument.The blank solution should be used as reference solution. Plot the absorbance against the wavelength and select wavelength of absorption maximum.

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CALCULATIONS

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From the molar concentration of iron solution and cell path length, calculate the molar absorbtivity of iron (II)-phenanthroline complex at the absorption maximum. Prepare a calibration curve by measuring the absorbance of each of standard solutions of wavelength of maximum absorbance. Measure the unknown in the same way. Prepare a calibration curve by plotting absorbance of standards against concentration in ppm. From this plot and the unknown's absorbance, determine the final concentration of iron in your unknown solution. Result: The amount of iron in given sample is _____________________

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6. DETERMINATION OF CONCENTRATION OF ALKALI METAL IONS BY FLAME PHOTOMETRY

Theoretical concentration (ppm)

Observed concentration (ppm)

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6. DETERMINATION OF CONCENTRATION OF ALKALI METAL IONS BY FLAME PHOTOMETRY Exp. No: Date: Aim: To determine the concentration of sodium and potassium in a given sample by flame photometry Principle: The estimation of sodium and potassium is based on the emission spectroscopy, which deals with excitation of electrons from ground state to higher energy state and coming back to its original state with emission of light. Trace amount of sodium and potassium can be determined by flame emission photometry at a wavelength of 589 nm and 766.5 nm respectively. The sample is sprayed into gas flame and excitation is carried out under carefully controlled and reproducible conditions. The desired spectral line is isolated by the use of interference filters or by a suitable slit arrangement in light-dispersing devices such as prism or grating, intensity of light is measured by a photo tube potentiometer. The intensity of light at 589 nm and 766.5 nm is approximately proportional to the concentrations of elements. After careful calibration of photometer with solutions of known compositions, it is possible to correlate the intensity of a spectral line of unknown solution with the amount of an element present that emits the particular radiation. Reagents and Apparatus (a) Deionized water (b) Sodium stock solution - dissolve 2.54g of dry sodium chloride in 1000ml of distilled water [1ml = 1mg of Na]. (c) Potassium stock solution - dissolve 1.91g of potassium chloride in distilled water to make the volume 1000ml.

[1ml = 1mg of K]. (d) Prepare various potassium and sodium solutions of different strength by diluting original stock solution (10ml

- 1 liter). (e) Standard measuring flasks (f) Pipette and beaker (g) Stopper conical flask (or) reagent bottle Procedure Estimation of sodium (a) Start the electrical supply and switch on the air supply. Stabilize the air and the needle should be steady at

the mark. (b) Switch on the gas and maintain the gas fuel mixture so that blue flame is seen through the viewing window.

Set the filter for reading at 589 nm. (c) Aspirate distilled water and adjust the galvanometer reading to zero.

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CALCULATIONS

Theoretical concentration (ppm)

Observed concentration (ppm)

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(d) Calibrate the instrument by using standard solutions of various concentrations and adjusting the galvanometer reading. Plot a standard curve between concentration and emission of standard solution.

(e) Use deionized water to bring the reading to zero mark. (f) Use sample solution and note down galvanometric reading. (g) Put off the fuel supply followed by air and then main switch. (h) Express the result of sodium content in mg/L. Estimation of potassium (a) Set the filter for reading at 166.5 nm. Proceed the determining of potassium by following the method

described for determination of sodium above. (b) Use standard potassium solution for preparation of standard curve. (c) Express the result of potassium content in mg/L. Result:

The amount of sodium present in the given sample from graph. = mg/L The amount of potassium present in the given sample from graph = mg/L

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7. Estimation of Sulphate ion by Turbidimetry

Concentration (ppm) Turbidity (NTU)

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7. Estimation of Sulphate ion by Turbidimetry Exp. No: Date: Aim: To estimate the amount of sulphate ion content in the given sample using turbidimetry. Principle: When light is passed through the suspension, part of the incident radiant energy is dissipated by absorption, reflection and refraction, while the remainder is transmitted when the suspension is viewed at right angles to the direction of the incident light, the system appears opalescent due to the reflection of light from the particles of suspension (Tyndall effect). The light is reflected irregularly and therefore the term scattered light is used for it. The measurement of the intensity of scattered light as a function of the concentration of suspended particles is done by the technique known as Turbidimetry or Nephelometry. The intensity of scattered light is measured at right angles to the direction of the incident light. Reagents & Apparatus (a) Potassium sulphate (b) Sodium chloride (c) Barium chloride (d) Glycerol (e) Alcohol (Ethanol) (f) Nephelometer / Turbidimeter Procedure Preparation of the standard solutions (a) Sulphate ion solution

Dissolve 0.4535g of dry potassium sulphate in distilled water and make the volume to 250ml. This solution has the sulphate concentration 1.0mg/ml.

(b) Sodium chloride - hydrochloric acid reagent Dissolve 25g of sodium chloride in 60-70ml of water. On dilution add 2ml of con. HCl. Dilute the solution to 100ml.

(c) Barium chloride Pass the crystals through a 20mesh sieve and take those, which are retained by the mesh. Dissolve 5gm of the salt in 100ml of water.

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CALCULATIONS

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(d) Glycerol - alcohol solution Take 100ml of glycerol in 500ml beaker and to it add 200ml of absolute ethanol. (or) Conditioning Reagent 50ml of glycerol + 30ml of con. HCl + 300ml of distilled water + 100ml of 95% C2H5OH + 75g of sodium chloride

(e) Preparation of suspended particles 1 Take seven 50 ml volumetric flask and label them 1, 2, 3, 4, 5, 6,7. Use the flask labeled as 1 for the

blank solution preparation. 2 Transfer 1, 2, 3, 4 & 5ml of the standard sulphate ion solution in the flaks number 2, 3, 4, 5 & 6. 3 To each flask add 30ml conditioning reagent solution. 4 Add 10ml of barium chloride solution to each flask and make the volume to 50ml. Allow each flask to

stand for 5 minutes. 5 The flask marked as 1 will have all the solution as under 3 and 4 except 2. 6 Use the flask labeled as 7 for unknown solution.

(f) Transfer the samples in sample tubes (which should be very clean inside and outside and should not contain any scratches). Note the reading on turbidity scale. Turbidity is measured in NTU (Nephelometric Turbidity Units). Prepare a standard curve by ploting NTU units vs the sulphate ion concentration. Then measure the sulphate ion concentration of the unknown.

Result:

The amount of sulphate ion present in the sample is ______________________

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CALCULATIONS

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8. PREPARATION AND CHARACTERISATION OF INORGANIC OXIDE MATERIAL- COMBUSTION METHOD Exp.No: Date: Introduction: Transition metal doped aluminous oxides are of technological importance due to their applications as lasers, TV phosphors and in fluorescent lamps. Fine particles of Cr3+ doped Al2O3 (ruby) used in ultra fine lasers and ultra fine optical devices. Ruby (0.2 to 1 atomic weight % of Cr3+ in Al2O3) crystallizes in hexagonal Wurtzite structure. Aim: To prepare ruby fine powders by combustion technique. Principle: It makes use of highly exothermic reaction at moderate temperature between the reactants to produce a flame due to spontaneous combustion resulting in very high temperature. This combustion results in a precursor or the product in finely divided form. Usually, a fuel and oxidizer are used to produce the combustion. Common fuels employed are hydrazine, glycine, tertra formyl triazide (TFTA). In a typical combustion reaction a mixture of nitrates(oxidizer) of the desired metals and a corresponding fuel are taken in solution form in a ceramic dish which is introduced into a preheated furnace (which is kept already at moderate temperature (500oC) for 5-10 minutes. The energy released at that moment is maximum and is able to sustain this energy long enough about 45 seconds for a reaction to form the desired product. The reaction produces 25.5 moles of gases N2, NO, N2O5 etc., for each moles of solid product formed. These gases break up large agglomerates and yield a porous mass of powder that fills the volume of reaction container. The surface area to volume ratio of combustion synthesized powder is usually very large due to large porosity of individual particles exhibit after the reaction. Procedure: 10g of Al(NO3)3. 9H2O and urea (4g) are dissolved in 10 ml of distilled water along with 35.5 mg of Cr(NO3)3.6H2O in a 250 ml beaker. The solution is then introduced into a low temperature furnace set at 5000C for 10 mins. Once the water is boiled off, the aluminium nitrate, chromium nitrate and urea react and ignite. The redox mixture undergoes combustion for 5 mins and gives a light pink coloured voluminious and foamy powder occoupying the entire volume of the beaker. The product is scratched out from the beaker, ground well and weighed. Result: The weight of the resulting powder is -------------- and identified to be ruby by XRD.

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9. Softening of Hard water by zeolite process

Expt. No : Date:

Aim To estimate removal capacity of the total hardness of the given hard water sample by zeolite.

A standard calcium ion solution (1mg of CaCO3 in 1 mL) and an approximately 0.01M solution of

EDTA are provided.

Principle Ethylenediaminetetraacetic acid (EDTA) is a well-known complexing agent. It forms

complexes with Ca2+ and Mg2+ ions in aqueous solution. The hardness producing Ca2+ and Mg2+ ions

form a wine red colored complex with Eriochrome Black–T (EBT) indicator in the presence of ammonia

buffer solution (pH around 10). When EDTA solution is added to the indicator complex, EDTA replaces

the indicator and a stable complex of Metal – EDTA is formed. The color of the solution will be steel

blue due to the release of EBT indicator into the solution.

Procedure Titration I - Standardisation of EDTA Pipette out 20 mL of the standard calcium ion solution into a clean conical flask. Add one test

tube full of ammonia buffer (NH4OH – NH4Cl) solution to maintain the pH around 10. Add three drops

of Eriochrome Black – T (EBT) indicator and titrate it against EDTA solution taken in the burette. The

end point is change of color from wine red to steel blue. Repeat the titration for concordant titre

values. Let ‘V1’ be the volume of EDTA consumed.

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Titration II - Estimation of Total Hardness Pipette out 20 mL of the sample hard water into a clean conical flask. Add one test tube full of

ammonia buffer (NH4OH – NH4Cl) solution and three drops of Eriochrome Black–T (EBT) indicator.

Titrate this mixture against standardized EDTA solution taken in the burette. The end point is the

change of color from wine red to steel blue. Repeat the titration for concordant titre value. Let ‘V2’ be

the volume of EDTA consumed.

Removal of hardness by zeolite ion exchange method:

Take 1 grams of zeolite in a clean beaker and add 100 ml of the given sample hard water. Stir

the content for 15 minutes, then filter it and proceed the filtrate for the analysis of total hardness.

Titration III - Estimation of Total Hardness after zeolite process Pipette out 20 mL of the sample hard water filtrate into a clean conical flask. Add one test

tube full of ammonia buffer (NH4OH – NH4Cl) solution and three drops of Eriochrome Black–T (EBT)

indicator. Titrate this mixture against standardized EDTA solution taken in the burette. The end point is

the change of color from wine red to steel blue. Repeat the titration for concordant titre value. Let ‘V3’

be the volume of EDTA consumed.

Note: Before starting this experiment the zeolite material has to be heated at 550°C for over night (at least 6 hours) to remove physisorbed impurities.

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Titration I - Standardization of EDTA

Standard hard water Vs EDTA

Burette reading (mL) S. No. Volume of Standard hard water (mL) Initial Final

Volume of EDTA (V1, mL)

20mL of Standard hard water = V1 mL of EDTA

∴ 20 x 1mg of CaCO3 = V1 mL of EDTA

∴ 1mL of EDTA = (20/V1) mg of CaCO3 eqvt.

= mg of CaCO3 eqvt.

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Titration II - Estimation of total hardness of the water before zeolite process Standardized EDTA Vs Sample hard water

Burette reading (mL) S. No. Volume of sample hard water (mL) Initial Final

Volume of EDTA (V2 mL)

20ml of given hard water = mL of EDTA

= V2 X 20/V1 mg of CaCO3 eqvt.

V2 X 20 X 1000 ∴1000mL of given hard water = mg of CaCO3 eqvt. V1 X 20 V2 X 1000 = mg / L V1 Total Hardness of water sample = V2

X 1000 ppm = ppm before zeolite process V1

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Titration III - Estimation of total hardness after zeolite process Standardized EDTA Vs Sample hard water filtrate

Burette reading (mL) S. No. Volume of sample hard Water filtrate (mL) Initial Final

Volume of EDTA (V3 mL)

20ml of given hard water filtrate = mL of EDTA

= V3 X 20/V1 mg of CaCO3 eqvt.

V3 X 20 X 1000 ∴1000mL of given hard water filtrate = mg of CaCO3 eqvt. V1 X 20 V3 X 1000 = mg / L V1 Total Hardness of water after zeolite process = V3

X 1000 ppm = ppm

V1

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Result: The removal of total hardness of the given sample of hard water by zeolite process was found

to be

Total hardness (before zeolite process) - Total hardness (after zeolite process) = ppm

Inference:

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Compound Equivalent weight Compound Equivalent weight

Cu2+ 63.54 NaOH 40

Fe,2+, Fe3+ 55.85 KOH 56

HCl 36.54 Na2CO3 53

HNO3 63 H2SO4 49

K2CO3 69 KCl 74.54

CaCO3 50 Ca(OH)2 37

ZnSO4. 7H2O 287.54 CaO 28

Ni2+ 59 K2Cr2O7 49

Na2S2O3. 5H2O 248 CuSO4. 5H2O 249.68

FeSO4. (NH4)SO4. 6H2O 392 EDTA 372.24

KMnO4 31.6 CH3COOH 60

FeSO4.2H2O 278

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EVALUATION OF PRACTICAL CLASSES

CONTINUOUS ASSESSMENT MARKS

Individual experiments = 10 Marks

Error Analysis for Continuous Assessment Text:

For Volumetric Analysis:

0 – 2 % = 10 marks

2– 3% = 9 marks

3 – 4% = 8 marks

> 4% = 5 marks

For Instrumental Analysis:

0 – 5% = 10 marks

5 – 6% = 9 marks

6 – 7% = 8 marks

> 7% = 5 marks

INTERNAL ASSESSMENT

Continuous Assessment Marks - 30 Marks

Viva - 20 Marks

Total - 50 Marks

TERM END EXAMINATION (50 Marks)

Practical Experiment = 30

Short Procedure = 10

Record = 10

For Volumetric Experiment (30 Marks)

0 – 2 % = 30 marks

2 – 3% = 27 marks

3 – 4% = 24 marks

> 4% = 15 marks

For Instrumental Experiment (30 Marks)

0 – 5% = 30 marks

5– 6% = 27 marks

6– 7% = 24 marks

> 7% = 15 marks