(APPLIED SCIENCE II)

Transcription

1 VPCOE VIDYA PRATHISHTHAN S COLLEGE OF ENGINEERING LAB MANUAL OF CHEMISTRY (APPLIED SCIENCE II) SECOND SEMESTER FOR FIRST YEAR ENGINEERING DEGREE COURSES Approved By HoD Dr. A. P. Hiwarekar Approved By Principal Dr. S. B. Deosarkar PREPARED BY Dr. APARNA G. SAJJAN

2 CONTENTS Scope & Objectives I Common laboratory glassware II Safety rules III 1. Determination of Alkalinity in given water sample by volumetric method To determine chloride (Cl ) content of water sample by Mohr s method To determine temporary & permanent hardness of water sample by EDTA method Spectrophotometric/colorimetric estimation of ferrous ions (Fe 2+ ) from the given solution To Study of corrosion of metals in medium of different ph Analysis of mixture of phosphoric acid and hydrochloric acid using indicators and ph meter. 7. To determine moisture, volatile matter & ash content of a given sample of coal Appendix References 28 Skills developed 28 Grid table 29

3 SCOPE & OBJECTIVES Water is one of the vital requirements for life on earth. The drinking water should be pure and free of pollutants. Water is a good solvent and picks up impurities easily. Pure water -- tasteless, colorless, and odorless - is often called the universal solvent. As water moves through soil and rock, it dissolves very small amounts of minerals and holds them in solution. Calcium & magnesium dissolved in water are the two most common minerals that make water "hard." One can test the water for its alkalinity, hardness and chloride content in the laboratory. These water tests, make you understand the nature of the test, the water condition being measured, and the significance of the test results. When doing laundry in hard water, soap curds lodge in fabric during washing to make fabric stiff and rough. Also causes graying of white fabric and the loss of brightness in colors. Continuous laundering in hard water can shorten the life of clothes. In addition, soap curds can deposit on dishes, bathtubs and showers, and all water fixtures. Hard water also contributes to inefficient and costly operation of water-using appliances. Heated hard water forms a scale of calcium and magnesium minerals that lead to inefficient operation or failure of water-using appliances. Pipes can become clogged with scale that reduces water flow and ultimately requires pipe replacement. High Chloride content in water imparts a pungent taste and also irritates the mucous membrane. Also leads to the bleaching (yellowing) of leaves of plants. If water with high chloride content is used in industries, the chloride reacts with the metals leading to corrosion. Of the eight experiments stated, three involve volumetric titrations for water analysis. A phase diagram is a map that tells us what phases will be stable at what conditions. One will understand & be able to find how these diagrams follow from plots of free energy curves. Corrosion is deterioration of essential properties in a material due to reactions with its surroundings. Weakening of iron due to oxidation of the iron atoms is a well-known example of electrochemistry (a branch of chemistry that studies the reactions that take place when an ionic and electronic conductor interfere) corrosion. This is commonly known as rust. This type of damage usually affects metallic materials, and typically produces oxide(s) and/or salt(s) of the original metal. Most structural alloys corrode merely from exposure to moisture in the air, but the process can be strongly affected by exposure to certain substances. By carrying out experiments in lab one can find the conditions as well as the rate of corrosion of different metals. Then it can be prevented by treatments such as passivation and chromateconversion will increase a material's corrosion resistance. The coal analysis for its moisture, volatile matter, ash and fixed carbon contents is carried under proximate analysis. It is useful to find out heating value (GCV) and also gives quick information about the quality of coal using which the suitability of the coal for a particular job can be assessed. I

4 COMMON LABORATORY GLASSWARES Burette Pipette Test-tube Measuring cylinder Conical flask Silica crucible with vented lid Volumetric flask Beaker Desiccator II

5 SAFETY RULES 1) Keep your bags in the cupboards below the working table 2) Keep your hands away from your face, while working. 3) Wash your hands with soap while leaving the lab. 4) Keep your working table neat and clean. 5) Read the procedure thoroughly before starting the experiment. 6) Know what to do in case of emergency. 7) Handle the apparatus and chemicals carefully. 8) Leave plenty of tap water after discarding the waste in the sink. 9) Do not waste the reagents/chemicals. III

6 EXPERIMENT NO. 1 Aim: Determination of Alkalinity in given water sample by volumetric method. Apparatus: Burette, Pipette, Conical flask, Dropper, measuring cylinder, Beaker etc. Chemicals: 0.02 N HCl, phenolphthalein indicator & methyl orange indicator. Theory: Pure water is neutral in nature with ph 7. Due to the presence of those minerals, which increase the concentration of OH ions in water, the ph of water increases & it becomes alkaline. These substances undergo dissociation or hydrolysis to form OH ions & the total amount of such titrable bases in water expressed as equivalent of CaCO 3 are referred to as total alkalinity. Alkalinity is divisible into bicarbonate alkalinity, carbonate alkalinity & in some cases hydroxide alkalinity. In most waters bicarbonates (HCO - 3 ) and carbonates (CO = 3 ) are the major bases, but others can also be important under particular conditions. Total alkalinity of natural waters may range from 5mg to several hundreds per litre (as CaCO 3 ). For biological purposes a total alkalinity over 40 mg of CaCO 3 /litre is considered to indicate hard waters. Alkalinity refers to the capability of water to neutralize acid. The presence of calcium carbonate or other compounds such as magnesium carbonate contribute carbonate ions to the alkalinity. Alkalinity is often related to hardness because the main source of alkalinity is usually from carbonate rocks (limestone), which are mostly CaCO 3. If CaCO 3 actually accounts for most of the alkalinity, hardness in CaCO 3 is equal to alkalinity. Since hard water contains metal carbonates (mostly CaCO 3 ) it is high in alkalinity. Environmental Impact: Alkalinity is important for aquatic life because it protects against rapid ph changes. Aquatic life functions best in a ph range of Higher alkalinity levels in surface waters will buffer acid rain & other acid wastes & prevents ph changes that are harmful to aquatic life. Effect on boilers: If water having high alkalinity is used for steam generation in boilers, it will lead to boiler troubles like caustic embrittlement, scale & sludge formation. The above alkalinities can be determined volumetrically by titrating water sample against standard acid using methyl orange and phenolphthalein indicators. OH + H + Detected by Phenolphthalein Indicator H 2 O (one step neutralization, P =M) Detected by Methyl orange Indicator HCO 3 + H + H 2 CO 3 (one step neutralization, M) CO H + Detected by Phenolphthalein Indicator H CO 3 (first step) HCO 3 + H + Detected by Methyl orange Indicator (Two step neutralization, 2P) H 2 CO 3 (second step)

7 Procedure: Part A: Preparation of solutions 1) Standard 0.02 N HCl solution: Dilute 1.72 ml of concentrated AR grade hydrochloric acid (11.6N) to 1 litre with distilled water in a volumetric flask. 2) Phenolphthalein indicator: Dissolve 500 mg of phenolphthalein in 50 ml ethanol & 50 ml distilled water (100 ml 50%ethanol). 3) Methyl orange indicator: Dissolve 50 mg of methyl orange in 100 ml distilled water. 0 ml V 1 ml (phenolphthalein end point) V2 ml (Methyl orange end point) Part B: Determination of alkalinity Check the ph of water sample at the beginning to find whether the sample is alkaline or not. If ph of the sample is above 8.00 then follow the procedure given below. Pipette out 50 ml of filtered water sample in a conical flask & add 4 drops of alcoholic phenolphthalein indicator to it. If the solution turns pink then titrate it with 0.02N HCl until colourless. Let this burette reading be V 1. To the same solution or to the solution, which remains colourless even after adding phenolphthalein indicator, add about 4 drops of methyl orange indicator. If the solution becomes yellow then continue titration till orange pink colour is obtained at the end point. Let this burette reading be V 2 from the beginning. This is called methyl orange end point. Repeat the titration for 2 more times & find out the constant burette reading. Reference table: Relation between V 1 & V 2 / P & M V 1 = 0 / P = 0 V 1 = V 2 / P = M V 1 = ½ V 2 / P = ½M V 1 > ½ V 2 / P > ½M Condition If phenolphthalein end point is zero, then alkalinity is due to only bicarbonate. If methyl orange end point is zero & only there is phenolphthalein end point, then the alkalinity is due to hydroxide alone. Hydroxide (OH ) alkalinity If phenolphthalein end point is exactly half the total titration, then only carbonate alkalinity is present If phenolphthalein end point is greater than half the total titration, then alkalinity is due to both carbonate & hydroxide. Alkalinity (ppm) Carbonate (CO 3 2 ) alkalinity M Bicarbonate (HCO 3 ) alkalinity M P M 2P ( M P )

8 V 1 < ½ V 2 / P < ½M Observations: If phenolphthalein end point is less than half the total titration, then alkalinity is due to both carbonate & bicarbonate P M 2P Sample No. 1) 2) 3) Phenolphthalein end point, V1 = P (Pink to Colourless) Readings (ml) Methyl orange end point, V 2 = M (Yellow to Orange pink) Ι ΙΙ ΙΙΙ Constant Ι ΙΙ ΙΙΙ Constant Calculations: All kinds of alkalinity are expressed in terms of CaCO 3 equivalents as parts per million ml of 1N HCl 50 g of CaCO 3 1 ml of 1N HCl 50 mg of CaCO 3 V ml of 0.02 N HCl 50 x V x 0.02 = V mg of CaCO 3 V mg of alkalinity is present in 50 ml of water sample For 1000ml of water sample i.e., 10 6 mg of water, alkalinity = (1000 x V)/50 = 20 V ppm Phenolphthalein alkalinity, P = 20 V1 ppm & Methyl orange alkalinity, M = 20 V 2 ppm 1) Calculation for condition 1: water sample having only bicarbonate alkalinity, V1 = 0 Methyl orange end point, V 2 = ml Methyl orange alkalinity, M = 20 V 2 ppm = ppm Alkalinity due to HCO 3 = M = ppm 2) Calculation for condition 2: water sample having only hydroxide alkalinity, V1 = V 2 Phenolphthalein end point, V1 = ml Phenolphthalein alkalinity, P = 20 V1 ppm = ppm Alkalinity due to OH = P = ppm 3) Calculation for condition 3: water sample having only carbonate alkalinity, V1= ½ V 2 Phenolphthalein end point, V1 = ml = ½ Methyl orange end point, V 2 = ml Phenolphthalein alkalinity, P = 20 V1 ppm = ppm Alkalinity due to CO 3 2 = 2P = ppm

9 4) Calculation for condition 4: water sample having both CO 3 2 & OH alkalinity, V1 > ½ V 2 Phenolphthalein end point, V1 = ml Phenolphthalein alkalinity, P = 20 V1 ppm = ppm Methyl orange end point, V 2 = ml Methyl orange alkalinity, M = 20 V 2 ppm = ppm Alkalinity due to OH = 2P M = = ppm 2 Alkalinity due to CO 3 = 2 ( M P ) = = ppm 5) Calculation for condition 5: water sample having both CO 3 2 & HCO 3 alkalinity, V1 < ½V 2 Phenolphthalein end point, V1 = ml Phenolphthalein alkalinity, P = 20 V1 ppm = ppm Methyl orange end point, V 2 = ml Methyl orange alkalinity, M = 20 V 2 ppm = ppm 2 Alkalinity due to CO 3 = 2P = = ppm Alkalinity due to HCO 3 = M 2P = = ppm Result: 1) 2) 3) Water sample Hydroxide (OH ) alkalinity, ppm Carbonate (CO 3 2 ) alkalinity, ppm Bicarbonate (HCO 3 ) alkalinity, ppm Related Questions: 1) Define Alkalinity. 2) What are the types of alkalinities of water? 3) What are the ph transition ranges of the indicators used? 4) What are the ill effects of alkaline water on boilers?

10 EXPERIMENT NO. 2 Aim: To determine chloride (Cl ) content of water sample by Mohr s method. Apparatus: Measuring cylinder, conical flask, volumetric flask, burette, pipette, dropper, etc. Chemicals: Standard 0.02N Silver nitrate solution & 5 % potassium chromate solution as indicator. Theory: Chlorides are present in water usually as NaCl, MgCl 2 & CaCl 2. Chlorides are not harmful but their concentrations above 250 ppm impart a peculiar taste to the water thus making the water unacceptable for drinking purposes. High concentration of chloride in a water sample indicates pollution. MgCl 2 & CaCl 2 are responsible for permanent hardness of water. Mohr s method is used for the determination of chloride ions in water sample, which is neutral or slightly alkaline. This method determines the chloride ion concentration of a solution by titration with silver nitrate. As the silver nitrate solution is slowly added, a precipitate of silver chloride forms. Ag + (aq) + Cl (aq) AgCl (s) (White ppt) The indicator used is dilute potassium chromate solution. When all the chloride ions have reacted, any excess silver nitrate added will react with chromate ions to form a red-brown precipitate of silver chromate. This procedure is known as Mohr s method. 2AgNO 3(aq) + K 2 CrO 4(aq) Ag 2 CrO 4(s) + 2KNO 3 (Red-brown ppt) The ph of the water sample should be between At ph higher than 8.5, silver ions get hydrated to form silver hydroxide. And at ph below 7 (acidic), potassium chromate is converted to potassium dichromate. Procedure: Preparation of solutions: 1) Standard 0.02N silver nitrate solution: Dissolve exactly g of dry solid AgNO 3 in distilled water & dilute it to 1 liter with distilled water in a volumetric flask, then store in a brown bottle. 2) 5% Potassium chromate solution: Dissolve 5g of solid K 2 CrO 4 in 100 ml distilled water. Determination of chloride: Back titration: Pipette out 50 ml of given water sample into a 250 ml conical flask & add 5 6 drops of potassium chromate as indicator. Now titrate this yellow coloured solution against standard 0.02N silver nitrate solution taken in burette. Initially white precipitate of silver chloride is formed which appears yellow due to the indicator. When all the chloride ions in water sample gets precipitated then addition of an extra drop of silver nitrate forms a reddishbrown precipitate of silver chromate. Thus formation of reddish-brown precipitate indicates the end point. Note down the burette reading & repeat the same titration for 2 more times. Let the constant burette reading be X ml.

11 Blank titration: A blank titration is also carried out as above with distilled water. In a 250 ml conical flask pipette out 50 ml distilled water & add 5 6 drops of potassium chromate as indicator. Now titrate it against standard 0.02N silver nitrate solution until the formation of reddish-brown precipitate at the end point. Note down the burette reading & repeat the same titration for 2 more times. Let the constant burette reading be Y ml. Observations: Blank titration Reading in ml I II III Constant reading (X) Initial Final Difference Back titration: Reading in ml I II III Constant reading (Y) Initial Final Difference Calculations: Volume of water sample taken for titration = 50ml. Volume of 0.02 N silver nitrate that has reacted with the chloride ions = Y X = = Z ml. 1 mole of AgNO 3 1 mole of AgCl 1 mole of AgCl 1 mole of Cl 1 mole of AgNO 3 1 mole of Cl 1000 ml 1N AgNO g of Cl Z ml 0.02 N AgNO 3 Z x 0.02 x 35.5 g of Cl Weight of chloride ions = Z x 0.02 x 35.5 = = A gm/ liter 50 Strength of chloride ions per litre = 1000 x A Or = mg chloride ions / litre = ppm of chloride ions Result: The given water Sample contains of chloride ions. Related Questions: 1) What is the type of titration used to determine the chloride content? 2) Name the salts that contribute for the chloride content in water. 3) What are the ill effects of chloride in water? 4) Name the indicator used in the above method.

12 EXPERIMENT NO. 3 Aim: To determine temporary & permanent hardness of water sample by EDTA method. Apparatus: Burette, Pipette, Conical flask, Dropper, Beaker etc. Chemicals: Ethylene diamine tetra acetic acid (EDTA) solution, zinc sulphate solution, ammonia buffer of ph 10 & Eriochrome black-t indicator. Theory: Hardness of water can be defined as the soap consuming capacity of water resulting in the formation of white curdy PPT due to the presence of salts of Ca & Mg salts. Ca/Mg + sodium stearate (C 17 H 35 COONa) Ca (C 17 H 35 COO) 2 / Mg(C 17 H 35 COO) 2 Salts Soap Calcium/Magnesium stearate (curd) Total hardness = It is due to the presence of all the salts of Ca & Mg. = Temporary hardness + Permanent hardness Temporary hardness: It is due to the presence of bicarbonates and soluble carbonates of Ca & Mg. Also called as carbonate hardness & can be removed by boiling. Ca(HCO 3 ) 2, Mg(HCO 3 ) 2, MgCO 3. Permanent hardness: It is due to the presence of sulphates, chlorides and nitrates of Ca & Mg. Also called as non-carbonate hardness, which cannot be removed by boiling. It requires lengthy treatment. CaCl 2, MgCl 2, CaSO 4, MgSO 4, Ca(NO 3 ) 2, Mg(NO 3 ) 2 etc. For determining suitability of water for domestic and industrial purpose, type of hardness and the amount of hardness is important. For the estimation of total hardness of a sample, disodium salt of EDTA is used. Na 2 EDTA forms 1:1 complex with divalent metal ions like Ca 2+, Mg 2+, Fe 2+, Zn 2+, etc. NaOOCH 2 C HOOCH 2 C N CH 2 CH 2 N Disodium-EDTA Structure CH 2 COOH CH 2 COONa The anion of EDTA (H 2 Y 4- ) is a strong chelating agent, which forms a stable anionic complex with divalent metal ions in basic medium. Therefore alkaline buffer of NH 4 OH & NH 4 Cl of ph-10 is used. In this complexometric titration, Eriochrome black -T is used as an indicator. This indicator forms unstable wine red coloured complex with metal ions, which dissociates on titration with EDTA solution. On dissociation, a strong metal ion- EDTA complex is formed and indicator is set free which gives blue colour to the solution at the end.

13 M 2+ + HIn 2 MIn + H + Metal ion Indicator Metal-Indicator complex Blue Wine red MIn + H 2 Y 4 MY 2 + HIn 2 + H + EDTA Metalion-EDTA Indicator Ionic form Complex Blue C O O CH 2 C CH 2 O 2 O N CH 2 Ca/Mg + EDTA M M = Ca / Mg CH 2 O N C CH 2 CH 2 O O C O Metal +2 EDTA 4 complex The following table gives the relation between the type of water sample & the degree of hardness Nature of water Soft Moderately hard Hard Very hard Hardness in ppm (CaCO 3 equivalent) Below 50 ppm ppm ppm Above 300 ppm

14 Procedure: Part A: Preparation of solutions 1) Standard 0.01 M ZnSO 4. 7H 2 O solution: Weigh accurately g of pure zinc sulphate & dissolve it in distilled water in a beaker. Then transfer it to a 250 ml volumetric flask & take washings of beaker into the volumetric flask. Dilute this solution upto the mark with distilled water and make it homogeneous. 2) 0.01m EDTA solution: Dissolve g of Disodium EDTA in one litre distilled water as above. 3) Buffer solution of ph-10: Dissolve 68 g of NH 4 Cl in distilled water. Add 572 ml of liquor ammonia and dilute to 1 litre with distilled water. 4) Eriochrome black-t indicator: Add 0.2 g of solid dye in 15 ml of triethanol amine & 5ml of ethanol. Part B: Standardisation of EDTA solution: Fill the burette with approximately 0.01m EDTA solution. Pipette out 25 ml of above standard ZnSO 4 solution in a conical flask, add 5ml of ph 10 buffer solution using measuring cylinder & then add 5 drops of Eriochrome black-t indicator. Titrate this wine red coloured solution against EDTA solution till the colour changes to blue at the end point. Repeat the same titration for 2 times and note the constant burette reading as X ml. Using this value calculate the exact molarity of EDTA solution. Observations and Calculations: Reading in ml Initial Final Difference I II III Constant reading (X) M 1 V 1 (ZnSO 4 ) = M 2 V 2 (EDTA) 0.01 x 25 = M 2 x X M 2 = ( 0 01 x 25 ) /X Molarity of EDTA = M 2 = M. Part C: Total hardness of water sample: Pipette out 50 ml of water sample in a conical flask, add 5ml of ph 10 buffer solution & then add 5 drops of Eriochrome black-t indicator. Titrate the wine red coloured solution against EDTA solution taken in burette till the colour changes to blue at the end point. Repeat the same titration for 2 times and note the constant burette reading as Y ml. Using this value calculate the total hardness of water sample. Observations and Calculations: Reading in ml Initial Final Difference I II III Constant reading (Y)

15 EDTA and Ca 2+ /Mg 2+ ions form 1:1 complex 1 mole EDTA 1 mole Ca 2+ /Mg 2+ 1 mole of CaCO 3 1 mole EDTA 100 g CaCO 3 Thus 1000 ml 1M EDTA 100 g CaCO 3 1ml 1M EDTA 1g CaCO 3 1ml 0.01M EDTA 1mg CaCO 3 Y ml M 2 M EDTA ( Y x M 2 ) / 0.01 mg of CaCO 3 mg of CaCO 3 = A 50 ml water sample contains A mg of CaCO ml water sample contains (A x 1000) /50 = 20 A mg of CaCO 3 But 1 mg of CaCO 3 per litre of water is 1 parts per million (ppm) of CaCO 3 Thus total hardness of water sample is = 20 A = ppm. Part D: Permanent hardness of water sample: Take 250 ml of hard water sample into a 500 ml beaker & boil it for about 30 minutes. Then cool & transfer the water into a 250 ml volumetric falsk and make the volume upto the mark with distilled water. Pipette out 50 ml of this water sample, add 5ml of ph 10 buffer, 5 drops of Eriochrome black- T indicator & titrate it against standard EDTA solution as given in part C. Repeat the same titration for 2 times and note the constant burette reading as P ml. Using this value calculate the permanent hardness of water sample. Observations and Calculations: Reading in ml I II III Constant reading (P) Initial Final Difference 1ml 0.01M EDTA 1mg CaCO 3 P ml M 2 M EDTA (P x M 2 ) / 0.01 mg of CaCO 3 mg of CaCO 3 = B 50 ml water sample contains B mg of CaCO ml water sample contains (B x 1000) / 50 = 20 B mg of CaCO 3 Thus Permanent hardness of water sample is = 20 B = ppm. Temporary hardness = Total hardness permanent hardness Temporary hardness = 20 A 20B = ppm

16 Result: Determinations Value 1) Strength of EDTA solution molar 2) Total hardness of given water sample ppm of CaCO 3 3) Permanent hardness of water sample ppm of CaCO 3 4) Temporary hardness of water sample ppm of CaCO 3 Conclusion: The water sample analysed has ppm of hardness hence it is. Related Questions: 1) Define hardness. What are the types of hardness of water? 2) What type of titration is used in the above method? Name the indicator used. 3) What are the ill effects of hard water on boilers?

17 EXPERIMENT NO. 4 Aim: Spectrophotometric / colorimetric estimation of ferrous ions (Fe 2+ ) from the given solution. Apparatus: Spectrophotometer or colorimeter, 50 ml volumetric flasks, Beaker etc. Chemicals: 0.25% ortho-phenanthroline solution, 10% hydroxylamine hydrochloride solution, ammonium acetate buffer solution, 0.2% sodium acetate solution, concentrated HCl, standard 0.1, 0.2, 0.3, 0.4 & 0.5 N iron solutions. Theory: Colorimetry is the science of measuring colors. One useful and often used way of determining the concentration of a chemical in a solution, if it has a color, is to measure the intensity of the color and relate the intensity of the color to the concentration of the solution. Several useful factors are very important. The Beer Lambert law, also known as Beer's law or Lambert Beer law is an empirical relationship that relates the absorption of light to the properties of the material through which the light is traveling. It states that the optical absorbance of a chromophore in a transparent solvent varies linearly with both the sample cell path length & the chromophore concentration. Absorbance is measured in a colorimeter or spectrophotometer by passing a collimated beam of light at wavelength λ through a plane parallel slab of material that is normal to the beam. For liquids, the sample is held in an optically flat, transparent container called a cuvette. Absorbance (A λ ) is calculated from the ratio of light energy passing through the sample (I 0 ) to the energy that is incident on the sample (I): Beer's Law follows: A λ = -log (I/I 0 ) A λ = ε λ bc ε λ = molar absorptivity or extinction coefficient of the chromophore at wavelength λ (the optical density of a 1-cm thick sample of a 1 M solution). ε λ is a property of the material and the solvent. b = sample pathlength in centimeters & c = concentration of the compound in the sample, in molarity (mol L -1 ) The reaction between ferrous ion and 1,10-phenanthroline to form a red complex serves as a sensitive method for determining iron (II). The molar absorptivity of the complex, [(C 12 H 8 N 2 ) 3 Fe] 2+, is 11,100 at 508 nm. The intensity of the color is independent of ph in the range 2 to 9. The complex is very stable and the color intensity does not change appreciably over long periods of time. Beer's law is obeyed. Hydroxylamine hydrochloride is used to reduce any ferric ion that is present. The ph is adjusted to a value between 6 & 9 by adding ammonia or sodium acetate. 1,10-phenanthroline is a bidentate ligand and only has 2 active sites to bond with iron, so the oxidation state it prefers to bond with is the Fe 2+ or Fe(II).

18 Fe phen (phen) 3 Fe(II) 1,10-phenanthraline Tris (1,10 phenanthraline) Iron (II) complex A B S O R B A N C E A (0,0) CONCENTRATION, C (mg/ml) Fig-1: Spectrum showing λmax at 508 nm Fig-2: Beer s plot [for standard Fe (II) solution] Procedure: Preparation of solutions: 1) 0.25% 1,10-phenanthroline solution: Dissolve exactly 0.25 g of solid 1,10- phenanthroline monohydrate in 100 ml of distilled water & slightly warm it. 2) 10% Hydroxylamine hydrochloride solution: Dissolve 10 g of solid Hydroxylamine hydrochloride in 100 ml of distilled water. 3) 5% Sodium acetate solution: Dissolve 5 g of Sodium acetate in 100 ml of distilled water. 4) Standard Ferrous ammonium sulphate solution: Weigh accurately about g of pure ferrous ammonium sulphate hexahydrate, dissolve it in distilled water & transfer the solution to a 1liter volumetric flask. Add 2.5mL of conc. sulfuric acid & dilute the solution to the mark with distilled water. Calculate the concentration of solution in mg of Fe / ml. 5) Unknown Fe(II) solution: Add about 0.2 g of the solid unknown & approximately 0.25 ml conc. sulfuric acid into a 100 ml volumetric flask. Dilute to the mark with distilled water. Determination of Fe (II): Into five 50 ml volumetric flasks, pipette out (volumetrically) 5, 10, 15, 20, and 25 ml portions of the standard iron solution. To another 50 ml volumetric flask pipette out 1 ml of unknown solution of iron (II). Put 5 ml of distilled water into another flask to serve as the blank. To each flask, including the "prepared unknown" (7 flasks), add 5 ml of the hydroxylamine solution, 5 ml of the 1,10 phenanthroline solution and 5 ml of the sodium acetate solution. Then dilute all the solutions to the 50 ml marks and allow them to stand for 10 minutes with occasional shaking.

19 Using the blank as a reference and any one of the iron solutions prepared above, measure the absorbance at different wavelengths in the interval from 400 to 700 nm. Take reading about 20 nm apart except in the region of maximum absorbance where intervals of 5 nm should be used. Plot the absorbance vs. wavelength and connect the points to from a smooth curve as shown in Fig-1. Select the proper wavelength to use for the determination of iron with 1,10-phenanthroline. Also, calculate the molar absorption coefficient, ε, at the wavelength of maximum absorption ( λ max) on the absorption curve (assume b = 1 cm). Measure the absorbance of each of the standard solutions and the unknown at the selected wavelength. Plot the absorbance vs. the concentration of the standards as shown in Fig-2. Note whether Beer's law is obeyed. Using the absorbance of the unknown solution calculate the % (w/w) iron in original solid sample. Observations: Serial No. Volume of standard Fe (II) solution Concentration In mg/ml Absorbance, A (Or %transmittance, T) A = log T 1. 5 ml ml ml ml ml 6. Blank 7. Unknown Calculations: Concentration of standard Fe solution = 0.01 mg/ml Using C 1 V 1 = C 2 V 2, calculate the concentration of all solutions. Now plot the graph of absorbance Vs. Concentration & from this standard graph, determine the concentration of unknown Fe (II) solution as shown below: A B S O R B A N C E A (0,0) Absorbance of Unknown solution Concentration of Unknown solution CONCENTRATION, C (mg/ml)

20 Result: The concentration of ferrous ion in a given solution is mg/liter. Related Questions: 1) State the Beer Lambert law or Beer's law. 2) Name the ligand used to complex Fe +2 ions. 3) What is the wavelength of maximum absorbance for [(C 12 H 8 N 2 ) 3 Fe] 2+ complex? 4) Why Hydroxylamine hydrochloride is added?

21 EXPERIMENT NO. 5 Aim: Study of corrosion of metals in medium of different ph. Apparatus: Beakers, metal bars, ph meter, sand paper, weighing balance, etc. Chemicals: Standard 2N hydrochloric acid and 2N sodium hydroxide (for preparing solutions of different ph). Theory: Corrosion is the primary means by which metals deteriorate or Corrosion is defined as the destruction of metals through chemical or electrochemical reactions taking place at its surface. Most metals corrode on contact with water (& moisture in the air), acids, bases, salts, oils, aggressive metal polishes, and other solid & liquid chemicals. Metals will also corrode when exposed to gaseous materials like acid vapors, formaldehyde, ammonia, and sulfur containing gases. Corrosion specifically refers to any process involving the deterioration or degradation of metal components. The best example is that of the rusting of iron/steel. If a piece of metal is immersed in a polar solvent like water, some of the metal ions leave the metal surface and go into the solution i.e., dissolution of metal starts. The metal continues to dissolve, more and more electrons are left back and a net negative charge is built up in the metal. Thus metal acquires a negative charge. The potential developed can be measured under standard conditions using standard hydrogen electrode as a reference electrode. It is called standard oxidation potential of metal. The metals having positive values are noble, they do not dissolve readily (metals like gold, platinum, silver, etc.). The metals having negative values of electrode potential are called active metals, which go into solution readily (like iron, zinc, magnesium, etc.). Metal Electrode Potential (V) Gold (Au 2+ ) Platinum (Pt 2+ ) Silver (Ag + ) Copper (Cu 2+ ) Hydrogen (H + ) 0 Iron ((Fe 2+ ) Zinc (Zn 2+ ) Aluminium (Al 3+ ) Magnesium (Mg 2+ ) This behaviour of metals depends upon the environmental conditions to which they are exposed. It can be studied by immersing metal plates in the solutions of different ph for a fixed or constant time. ph = log [ H + ]

22 Procedure: Take 5 metal plates (mild steel or zinc) of size 6cm x 2.5cm having same thickness. Rub the metallic plates with sand paper to remove any corrosion product on it. Weigh them separately and note down their respective weights. Beaker Electrolyte solution Metal plate Observations: Corrosion assembly Prepare solutions having different ph such as 1.5, 2.0, 3.0, 5.0 & 8.0 units by mixing standard 2N HCl & 2N NaOH. Measure their ph using ph meter. Take five 50 ml beakers, label them and take about 30 ml above solutions in the beaker. Dip the previously weighed metallic strips in the beaker such that 4/5 th portion is immersed in the solution. Note down the time. After one hour take out the metallic plates from the beaker, dry them in air and then weigh. Note down the respective weights of the plates. Plate No. ph of the solution Weight of the plate Before After Loss in weight (In 1 hr) Loss/gm/hr unit unit unit unit unit Calculations: Loss in weight (in 1 hr.) = Before weight After weight = X gm Weight loss / before weight /hr. = X gm = gm Loss of metal /gram/hr. = X / Before weight = gm Plate No. 1: Plate No. 2: Plate No. 3: Plate No. 4: Plate No. 5:

23 Result: Weight loss / gm / hour is maximum in ph solution. Weight loss / gm / hour is minimum in ph solution. Conclusion: Related Questions: 1) Define corrosion. 2) How does ph affects the rate of corrosion? 3) Name the series in which metals and their alloys are arranged according to their anodic or cathodic nature.

24 EXPERIMENT NO. 6 Aim: Analysis of mixture of phosphoric acid and hydrochloric acid using indicators and ph meter. Apparatus: Burette, pipette, conical flask, burette stand, beaker, magnetic stirrer, ph-meter, glass electrode, etc. Chemicals: 0.1 N sodium hydroxide, standard buffer solution of Known ph and 3:1 phenolphthalein naphtholphthalein indicator mixture. Theory: An acid or a base is quantitatively determined by titration using ph meter or acidbase indicators to detect the equivalence point/end point. ph-meter is frequently used because the advantage that one actually monitors is the change in ph at the equivalence point rather than just observing the colour change of a visual indicator. This eliminates any indicator blank error. The titration of a mixture of phosphoric acid and hydrochloric acid is complicated by the fact that phosphoric acid is a triprotic acid with Ka 1 = 7.5x10-3, Ka 2 = 6.2x10-8, and Ka 3 = 4.8x Ka 1 is sufficiently large that the first proton from phosphoric acid cannot be differentiated from strong acids like hydrochloric acid. The second dissociation of phosphoric acid is varies significantly from the first. The second proton can be neutralized and differentiated from the first phosphoric acid proton and the strong acid proton. At the first equivalence point: ph = 4.7 H 3 PO 4 (aq) + OH (aq) At the second equivalence point: ph = 9.3 H 2 PO 4(aq) + H2O (l) H 2 PO 4 (aq) + OH (aq) HPO 4 2 (aq) + H 2 O (l) Neutralization of the third proton of phosphoric acid does not produce an appreciable break in the titration curve. This is ultimately because Ka 3 is very small and acids with small Ka' s produce small breaks. Because Ka 3 is so small, the basicity (proton accepting ability) of the phosphate ion is large, and it undergoes hydrolysis producing hydroxide ion. HPO 4 2 (aq) + OH (aq) PO 4 3 (aq) + H 2 O (l) Overall reaction: H 3 PO 4 (aq) + 3OH (aq) PO 4 3 (aq) + 3H 2 O (l) To express H + ion concentration, ph scale is used. This ph can be measured directly using a ph meter. ph = log H + ion concentration Or ph = log [H + ]. The titration curve for a mixture of phosphoric and hydrochloric acids are illustrated here. The first break in the mixed acid curve indicates the amount of hydrochloric acid plus the amount of the phosphoric acid. The amount of phosphoric acid in the sample is indicated by the difference between first and second breaks in the titration curve. The first equivalence point volume (25.0 ml) permits calculation of the total meq of HCl + (meq H 3 PO 4 )/3 since the first proton of H 3 PO 4 is neutralized.

25 In acid-base titrations addition of base to the acid, decreases the H + ion concentration of the reaction mixture. This change in ph (equivalence point) can be measured by phmeter or the end point can be found out by using visual indicators. When a pair of electrodes namely ph sensitive glass electrode and reference electrode are dipped in an aqueous solution, they generate e.m.f. which is proportional to the ph of the solution. This e.m.f. (E) is temperature dependent & is given by the Nernst equation: RT E = E 0 ln [H + ] F RT E = E 0 log [H + ] F RT E = E 0 + ph F Where - E 0 = voltage that depends on the reactants and the products in the reaction. R = Gas constant, J mol -1 K -1 T = Absolute temperature in Kelvin. F = Faraday, the charge on one mole of electrons (96485 coulombs). Procedure: Preparation of solutions: 1. Standard 0.1N sodium hydroxide solution: Weigh accurately 4 g of pure NaOH in a clean watch glass and transfer it to a beaker. Dissolve it in distilled water and collect the washings of the watch glass in the same beaker. Then transfer it to a 1liter volumetric flask & take washings of beaker into the volumetric flask. Dilute this solution upto the mark with distilled water and make it homogeneous % Methyl orange indicator: Weigh 0.01 g of solid methyl orange and dissolve it in 100ml distilled water % Phenolphthalein indicator: Weigh 0.05 g of solid phenolphthalein and dissolve it in 100ml 50% ethanol (50ml ethyl alcohol + 50ml distilled water). Determination of mixture of HCl & H 3 PO 4 : Measurement of ph of unknown sample consists of two steps. First step is to standardise the ph meter using a known standard buffer solution (usually of ph 7) at room temperature. The second step involves the measurement of ph of unknown solution.

26 Standardisation of ph meter: Switch on the instrument by turning the control ON and set the function switch to standard-by, STD BY position. Rinse the electrode pair with distilled water and wipe them carefully with tissue or filter paper. Take the beaker containing standard buffer solution of ph 7.00 and dip the electrodes in it. Set the function switch to the ph position. Set the buffer value on digital display to read 7.00 by rotating the Standardise knob. Put back the function switch to STD BY mode. Now without disturbing the Standardise knob, complete all the ph measurements of titration. Acid-Base titration using ph-meter: Pipette out 25ml of acid mixture (0.1N HCl N H 3 PO 4 ) in a 100ml beaker. Rinse the glass electrode with distilled water and wipe it with filter paper. Now dip the electrode in the beaker containing acid solution. Set the function switch to ph mode and note down the ph of the solution displayed on the digital display of ph meter. Fill the burette with standard 0.1N sodium hydroxide solution. Add 5 ml of NaOH to the beaker containing acid solution and stir it using a magnetic stirrer. Note down the ph of the solution. Similarly measure the ph of the reaction mixture after adding 10, 15, 20, 25,30,35,40 and 45 ml of NaOH from burette. Watch for the region where the ph begins to change rapidly with each added portion of titrant. As the ph begins to change more rapidly, add the titrant in smaller portions. When you have passed the equivalence point by several ml, there is no reason to continue any further in the titration. Then plot graphs of ph versus volume of NaOH added and ph/ ml versus volume of NaOH. From the graph, find out the end point of titration. Acid-Base titration using indicator: Pipette out 25 ml of acid mixture (0.1N HCl N H 3 PO 4 ) in a conical flask and add 2-3 drops of methyl orange indicator. Titrate this orange red solution against standard 0.1N NaOH till the solution becomes yellow at the end point (first). After recording the burette reading, to the same flask add 2-3 drops of phenolphthalein indicator and continue the titration till the solution turns pink at the end point (second). Record the total burette reading. Repeat the titration and Compare the results with the first method. Observations: For ph-meter method Volume of NaOH added, (ml) ph ph ml ph / ml

27 Plot the following graphs: Graph I (ph Vs volume of NaOH) Graph II ( ph/ ml ( Vs volume of NaOH) ph ph ml ml of NaOH (0,0) ml of NaOH From the graphs find out the end/equivalence points of the titration = & ml Observations: For Indicator method Reading in ml Initial Final Difference Methyl orange end point, V 1 = M (Orange pink to Yellow) Readings (ml) Phenolphthalein end point, V2 = P (Colourless to Pink) Ι ΙΙ ΙΙΙ Constant Ι ΙΙ ΙΙΙ Constant End point of titration is = X = & ml 1.1 x 5ml = C 2 x 50 1) For 5 ml solution, C 2 = (0.01 x 5) / 50 = ) For 10 ml solution, C 2 = (0.01 x 10) / 50 = ) For 15 ml solution, C 2 = (0.01 x 15) / 50 = ) For 20 ml solution, C 2 = (0.01 x 20) / 50 = ) For 25 ml solution, C 2 = (0.01 x 25) / 50 = Result: Related Questions: 1) What is the ph value at the first and the second equivalence point? 2) Why standard buffer solution of ph 7 is used? 3) Name the two indicators used in this titration. 4) How end point of titration is detected using ph meter?

28 EXPERIMENT NO. 7 Aim: To determine moisture, volatile matter & ash content of a given sample of coal. Apparatus: Silica crucible with vented lid, electric oven, Muffle furnace, spatula, desiccator, pair of tongs, weighing balance, long legged tongs, etc. Chemicals: Powdered coal sample. Theory: Coal is a primary, solid, fossil fuel. Coal sample has to be analysed before using it in any field/industry to find out its quality & suitability. Moisture, volatile matter & ash content of coal are determined under proximate analysis. This method is simple & quick and is used primarily to determine the suitability of coal for coking, power generation or for iron ore smelting in the manufacture of steel. Coal comes in following main types or ranks: Peat, lignite or brown coal, bituminous coal, anthracite & Graphite. Each type of coal has a certain set of physical parameters which are mostly controlled by moisture, volatile content (in terms of aliphatic or aromatic hydrocarbons) & carbon content. The carbon content is lowest in peat and highest in anthracite. Moisture Moisture is an important property of coal, as all coals are mined wet. Groundwater and other extraneous moisture is known as adventitious moisture and is readily evaporated. Moisture held within the coal itself is known as inherent moisture & is analysed. Moisture reduces the calorific value of coal and considerable amount of heat is wasted in evaporating it during combustion. Moisture may occur in four possible forms within coal: Surface moisture, Hydroscopic moisture, Decomposition moisture & Mineral moisture. Total moisture is analysed by loss of mass of sample by Drying in air at 100 to 105 C (210 to 220 F) and relative loss of mass is determined. T otal moisture content of the coal should be as low as possible. Volatile matter Volatile matter in coal refers to the components of coal, except for moisture, which are liberated at high temperature in the absence of air. This is usually a mixture of short and long chain hydrocarbons, aromatic hydrocarbons & some sulfur. Volatile matter of the coal is related to the length of the flame, smoke formation & ignition characteristics. High volatile matter coal gives long flame, high smoke & relatively low heating values. Volatile matter content should be therefore as low as possible but minimum 20% is required for the ignition of coal. In Australian & British laboratories this involves heating the coal sample to 900 ± 5 C (1650 ±10 F) for 7 minutes in a cylindrical silica cruci ble in a muffle furnace. American Standard procedures involve heating to 950 ± 25 C (1740 ± 4 5 F) in a vertical platinum crucible. Ash Ash content of coal is the non-combustible residue left after coal is burnt. It represents the bulk mineral matter after carbon, oxygen, sulfur and water (including from clays) has been driven off during combustion. It consists of inorganic matter like silica, alumina, iron oxide, lime, magnesia, etc. Ash reduces the heating value of coal, reduces air supply in furnaces

29 and also requires labour (extra cost) for its regular disposal. Therefore ash content of coal should be as low as possible. Analysis is fairly straightforward, with the coal thoroughly burnt and the ash material expressed as a percentage of the original weight. Fixed carbon The fixed carbon content of the coal is the carbon found in the material which is left after volatile materials are driven off. This differs from the ultimate carbon content of the coal because some carbon is lost in hydrocarbons with the volatiles. More the fixed carbon content, higher will be the calorific value of coal. Fixed carbon is determined by removing the mass of volatile matter, moisture and ash determined by the above tests, from the original mass of the coal sample. Procedure: A. Determination of Inherent Moisture: Transfer about 1g (known quantity) of powdered air dried coal sample into a previously weighed silica crucible. Place the open crucible with sample in an electric oven and heat it at about o C for an hour. Take out the crucible after one hour from the oven and cool it in a desiccator (containing moisture absorbing anhydrous calcium chloride). Then weigh the crucible with sample and repeat the process of heating, cooling & weighing till constant weight is obtained. Calculate the loss in weight. B. Determination of Volatile matter: The dried sample of coal after determining moisture content is closed with a vented lid. The closed crucible is then heated in a Muffle furnace maintained at 925 ± 20 o C for exactly 7 minutes. The crucible is taken out from Muffle furnace carefully with the help of long legged tongs. It is first cooled in air and then in a desiccator. When the crucible attains room temperature it is weighed. Calculate the loss in weight. C. Determination of Ash: Transfer about 1g (known quantity) of powdered air dried coal sample into a previously weighed silica crucible. Place the open crucible with sample in a Muffle furnace maintained at 725 ± 25 o C for about 40 minutes or till constant weight is obtained. Coal burns in open and the residue left is ash. Take out the crucible from Muffle furnace carefully using long legged tongs. Cool the hot crucible first in air and then in a disiccator. Weigh the crucible and find out the amount of unburnt residue left (ash). D. Determination of Fixed Carbon: The percentage of fixed carbon is determined indirectly by substrating the sum total of percentages of moisture, volatile matter and ash from 100. Observations and Calculations: A. For Moisture: 1. Weight of empty crucible = W 1 = g. 2. Weight of crucible + Coal sample = W 2 = g. 3. Weight of Coal sample before heating = W 2 W 1 = W 3 = g. 4. Weight of crucible + Sample after heating for 1 hr at o C = W 4 = g. 5. Weight of Coal sample after heating = W 4 W 1 = W 5 = g.

30 6. Loss in weight of sample due to moisture = W 3 W 5 OR W 2 W 4 = W M = g. % Of Moisture in coal = Weight of moisture x 100 = W M x 100 Weight of coal (before heating) W 3 = % Observations and Calculations: B. For Volatile matter: 1. Weight of empty crucible = W 1 (W 1 from part A) = g. 2. Weight of crucible + moisture free coal sample = W 2 (W 4 from part A) = g. 3. Weight of moisture free sample (before heating) = W 2 W 1 = W 3 = g. 4. Weight of crucible + Sample after heating for 7 mins. at 925 ± 20 o C = W 4 = g. 5. Weight of Sample after heating = W 4 W 1 = W 5 = g. 6. Loss in weight of sample due to volatile matter = W 3 W 5 = W VM = g. % Of Volatile matter in coal = Weight of volatile matter x 100 = W VM x 100 Weight of coal (before heating) W 3 = % Observations and Calculations: C. For Ash: 1. Weight of empty crucible = W 1 = g. 2. Weight of crucible + Coal sample = W 2 = g. 3. Weight of Coal sample (before heating) = W 2 W 1 = W 3 = g. 4. Weight of crucible + Sample after heating for 40 mins. at 725 ± 25 o C = W 4 = g. 5. Weight of Ash formed = W 4 W 1 = W A = g. % Of Ash in coal = Weight of Ash x 100 = W A x 100 Weight of coal (before heating) W 3 D. For Fixed carbon (FC): = % % Of Fixed Carbon = 100 (% Moisture + % Volatile matter + % Ash) = 100 ( ) = %

31 Result: The coal sample analysed contains: Moisture = % Volatile matter = % Ash = % Fixed Carbon = % Conclusion: Related Questions: 1) Define coal. What are the types of analysis of coal? 2) What is the temperature time limit of heating for volatile matter analysis? 3) For moisture content determination heating is carried out in which equipment? 4) What is the significance of proximate analysis of coal? 5) How does ash and fixed carbon affect the quality of coal?

32 Table-I: ph Value (Refer Experiment No. 6) APPENDIX Table-II: ph Value (Refer Experiment No. 7) Fuel Higher Calorific Value (Gross Calorific Value - GCV) Kcal/Kg kj/kg Btu/lb Anthracite ,500-34,000 14,000-14,500 Bituminous coal ,000-23,250 7,300-10,000 Charcoal ,600 12,800 Coal ,000-27,000 8,000-14,000 Coke ,000-31,000 12,000-13,500 Lignite ,300 7,000 Peat ,800-20,500 5,500-8,800 Semi anthracite ,700-32,500 11,500-14,000 Wood (dry) ,400-17,400 6,200-7,500

33 Table-III: Electromagnetic spectrum (Refer Experiment No. 4) Serial No. Radiation /Rays Wavelength range 1 Radio waves 3 x 10 5 cm 2 Micro eaves 30 cm 3 Far Infrared 0.01 cm 4 Near Infrared 1000 nm 5 Visible nm i Red 750 nm ii Orange 650 nm iii Yellow 590 nm iv Green 530 nm v Blue 490 nm vi Indigo 420 nm vii Violet 400 nm 6 Ultraviolet nm 7 Vacuum UV nm 8 X - rays nm 9 Gamma rays nm Table-IV: Galvanic series (Refer Experiment No. 5) Most susceptible to corrosive attack (Less Noble) Anodic end Least susceptible to corrosive attack (More Noble) Cathodic end Magnesium and its alloys Zinc and its alloys Aluminium and its alloys Mild steel Cast Iron Stainless steel (active type) Lead Tin Brasses Gun metal Copper Monel Titanium and its alloys Stainless steel (passive type) Silver Gold Platinum

34 REFERENCES: 1) Laboratory Manual on Engineering Chemistry, Sudharani (Dhanpat Rai Publishing Company). 2) Vogel s Textbook of Quantitative chemical analysis, J. Mendham et.al. (Pearson Education). 3) Advanced Inorganic Analysis, Agarwal & Keemtilal, Pragati prakashan. 4) Chemical tables, Dr N. S. Gnanapragasam, (Sultan Chand & sons). DEVELOPMENT OF SKILLS This Lab Manual intends to develop the intellectual and motor skills of student. The skills mentioned below will be developed through the experiments performed in this laboratory. Intellectual Skills: I-1 : To understand and identify the concepts. I-2 : To Discriminate / Classify / Identify. I-3 : To Investigate / Test / Verify properties or characteristics. I-4 : To Interpret test results or numerical values. I-5 : To locate faults. I-6 : To plan and design. Motor Skills: M-1 : Skill to sketch the circuit diagram / block diagram / graph. M-2 : Skill to select, handle and operate the equipment and reagents. M-3 : Skill to measure the values / note down the observations. M-4 : Skill to follow systematic procedure or sequence of operations step by step. M-5 : Skill to observe the performance.

35 In order to develop these skills for each experiment, important skills have been identified. While performing the experiment, it is necessary to focus on such important skills. Following table shows a grid of experiments and relevant skills. GRID TABLE No. Experiment No. & Title Intellectual skills Motor skills I 1 I 2 I 3 I 4 I 5 I 6 M 1 M 2 M 3 M 4 M Determination of Alkalinity in given water sample by volumetric method. To determine chloride (Cl ) content of water sample by Mohr s method. To determine temporary & permanent hardness of water sample by EDTA method. Spectrophotometric/colorimetric estimation of ferrous ions (Fe 2+ ) from the given solution. To Study of corrosion of metals in medium of different ph. Analysis of mixture of phosphoric acid and hydrochloric acid using indicators & ph meter. To determine moisture, volatile matter & ash content of a given sample of coal.