A. TITLE: Complexometry Titration and its ApplicationB. PURPOSE: 1. To make and determine (standardization) of Na-EDTA solution 2. To determine the total hardness of Kenjeran well waterC. BASIC THEORY : Complexometry TitrationComplexometric titration (sometimes chelatometry) is a form of volumetric analysis in which the formation of a colored complex is used to indicate the end point of a titration. Complexometric titrations are particularly useful for the determination of a mixture of different metal ions in solution. An indicator capable of producing an unambiguous color change is usually used to detect the end-point of the titration.Basic theory of complexometry titration with EDTA is the forming of complex compound between some metal (such as: Ca, Mg, Ni, Zn, Cu, etc) with EDTA. Metals will forms complex with EDTA at different pH, Ca2+ and Mg2+ react well at pH 8 10. EDTA (Etilen Diamine Tetra Acetate) is an acid base 4 (H4Y). but, which is often used is the natrium salt (Na2H2Y). the forming of complex between metals ions and EDTA according to pH of solution. Indicator that is used are EBT (Enochrome Black T) and Kalgamit. That indicator is a weak acid basic 3 (H3In). dissociating equilibrium of that indicator will give some colors and forming complex 1 : 1 with total metal ion, so, can give the color change at the end of reaction.Reactions Indicator: H2In- HIn2- + H+Red Blue With metal ion: Ca2+, Mg2+, Zn2+, Ni2+:Mg2+ + HIn2- MgIN- + H+Red grape With EDTA: MgIn- + H2Y2- MgH2Y2- MgH2Y + In3-Red grapeIn3- + H2O HIn- + OH-Blue At equivalent point:Sum of equivalent Mg2+ = sum of equivalent EDTASo, the changing color through titration is : solution that contain of metal ion like the statement above after added by EBT indicator will be change into red grape, after that, after theres happen an equivalent between metal ion with EDTA can be seen from the form of blue from indicator in HIn2-.In theory, any complexation reaction can be used as a volumetric technique provided that:1. The reaction reaches equilibrium rapidly after each portion of titrant is added.2. Interfering situations do not arise. For instance, the stepwise formation of several different complexes of the metal ion with the titrant, resulting in the presence of more than one complex in solution during the titration process.3. A complexometric indicator capable of locating equivalence point with fair accuracy is available.In practice, the use of EDTA as a titrant is well established.

Reagent EDTAEDTA, ethylenediaminetetraacetic acid, has four carboxyl groups and two amine groups that can act as electron pair donors, or Lewis bases. The ability of EDTA to potentially donate its six lone pairs of electrons for the formation of coordinate covalent bonds to metal cations makes EDTA a hexadentate ligand. However, in practice EDTA is usually only partially ionized, and thus forms fewer than six coordinate covalent bonds with metal cations.Disodium EDTA is commonly used to standardize aqueous solutions of transition metal cations. Disodium EDTA (often written as Na2H2Y) only forms four coordinate covalent bonds to metal cations at pH values 12. In this pH range, the amine groups remain protonated and thus unable to donate electrons to the formation of coordinate covalent bonds. Note that the shorthand form Na4-xHxY can be used to represent any species of EDTA, with x designating the number of acidic protons bonded to the EDTA molecule.EDTA forms an octahedral complex with most 2+ metal cations, M2+, in aqueous solution. The main reason that EDTA is used so extensively in the standardization of metal cation solutions is that the formation constant for most metal cation-EDTA complexes is very high, meaning that the equilibrium for the reaction:M2+ + H4Y MH2Y + 2H+lies far to the right. Carrying out the reaction in a basic buffer solution removes H+ as it is formed, which also favors the formation of the EDTA-metal cation complex reaction product. For most purposes it can be considered that the formation of the metal cation-EDTA complex goes to completion, and this is chiefly why EDTA is used in titrations / standardizations of this type.IndicatorsTo carry out metal cation titrations using EDTA, it is almost always necessary to use a complexometric indicator to determine when the end point has been reached. Common indicators are organic dyes such as Fast Sulphon Black, Eriochrome Black T, Eriochrome Red B, Patton Reeder, or Murexide. Color change shows that the indicator has been displaced (usually by EDTA) from the metal cations in solution when the endpoint has been reached. Thus, the free indicator (rather than the metal complex) serves as the endpoint indicator. The end point of this titration is the change from blue color (EBT) to colorless. and when EBT form weak complex with the ca and mg ion present in the solution but after the addition with titration with EDTA all the metal ion leaving EBT which formed weak and unstable compound react with EDTA forms stable and stable complex.Well WaterShallow pumping wells can often supply drinking water at a very low cost, but because impurities from the surface easily reach shallow sources, a greater risk of contamination occurs for these wells when they are compared to deeper wells.Chemical contamination is a common problem with groundwater. Nitrates from sewage or fertilizer are a particular problem for children. Pollutant chemicals include pesticides and volatile organic compounds from gasoline, dry-cleaning, the fuel additive methyl tert-butyl ether (MTBE), and perchlorate from rocket fuel, airbag inflators, and other artificial and natural sources.Several minerals are also contaminants, including lead leached from brass fittings or old lead pipes, chromium VI from electroplating and other sources, naturally occurring arsenic, radon, and uraniumall of which can cause cancerand naturally occurring fluoride, which is desirable in low quantities to prevent tooth decay, but can cause dental fluorosis in higher concentrations.[8]Some chemicals are commonly present in water wells at levels that are not toxic, but can cause other problems. Calcium and magnesium cause what is known as hard water, which can precipitate and clog pipes or burn out water heaters. Iron and manganese can appear as dark flecks that stain clothing and plumbing, and can promote the growth of iron and manganese bacteria that can form slimy black colonies that clog pipes.

Hard Water/ Hardness WaterHard water is water that has high mineral content (in contrast with "soft water"). Hard drinking water is generally not harmful to one's health,[1] but can pose serious problems in industrial settings, where water hardness is monitored to avoid costly breakdowns in boilers, cooling towers, and other equipment that handles water. In domestic settings, hard water is often indicated by a lack of suds formation when soap is agitated in water, and by the formation of limescale in kettles and water heaters. Wherever water hardness is a concern, water softening is commonly used to reduce hard water's adverse effects.Water's hardness is determined by the concentration of multivalent cations in the water. Multivalent cations are cations (positively charged metal complexes) with a charge greater than 1+. Usually, the cations have the charge of 2+. Common cations found in hard water include Ca2+ and Mg2+. These ions enter a water supply by leaching from minerals within an aquifer. Common calcium-containing minerals are calcite and gypsum. A common magnesium mineral is dolomite (which also contains calcium). Rainwater and distilled water are soft, because they contain few ions.[2]The following equilibrium reaction describes the dissolving/formation of calcium carbonate scale:CaCO3 + CO2 + H2O Ca2+ + 2HCO3Calcium carbonate scale formed in water-heating systems is called limescale.Calcium and magnesium ions can sometimes be removed by water softeners.Temporary hardness is a type of water hardness caused by the presence of dissolved bicarbonate minerals (calcium bicarbonate and magnesium bicarbonate). When dissolved these minerals yield calcium and magnesium cations (Ca2+, Mg2+) and carbonate and bicarbonate anions (CO32-, HCO3-). The presence of the metal cations makes the water hard. However, unlike the permanent hardness caused by sulfate and chloride compounds, this "temporary" hardness can be reduced either by boiling the water, or by the addition of lime (calcium hydroxide) through the softening process of lime softening. Boiling promotes the formation of carbonate from the bicarbonate and precipitates calcium carbonate out of solution, leaving water that is softer upon cooling.

D. Tools and materials: Volumetric flask 500 mL Pipette Volumetric pipette Erlenmeyer Burette CaCO3 Aquades HCl Na-EDTA solution 0,01 M CaCl2 solution EBT

E. PROCEDURE:Determination of standardization Na-EDTA solution 0,01 M with CaCl2 as standard solution

0,4 grams of CaCO3 Moved into the volumetric flask 500 mL used water 100 mL Added HCl 1 : 1 drop by drop until gladak gas stopped Diluted with water until the limit sign Shake until mixed perfectly Washed and filled with Na-EDTA solution 0,01 M Pipette with volumetric pipette 50 mL of CaCl2 solution Entered into the Erlenmeyer 300 mL Added 5 mL of buffer solution pH 10 Added 5 drops of EBT indicator Titrated with Na-EDTA solution 0,01 M Stopped titration when theres changing color from redish grape to blue

Changing Color

Read and note the number on burette when the first and the end of titration Determine and note Na-EDTA solution that used in titration Calculated the mean concentration of Na-EDTA

The mean concentration of Na-EDTA

Determination the sum of the hardness of Kenjeran well water

25 mL of sample water Pipette and dropped to Erlenmeyer Added 2 mL buffer solution pH 10 Added 3 drops of BET Titration with EDTA 3x

Blue (preciously until red color disappear)

Average hardness of well waterCalculated the sum of the hardness in CaCO3 salt per liter of water (in the form of ppm)

F. EXPERIMENT RESULT:No.Procedure of ExperimentExperiment resultHypothesisConclusion

1. 0,4 grams of CaCO3Determination of standardization Na-EDTA solution 0,01 M with CaCl2 as standard solution

Moved into the volumetric flask 500 mL used water 100 mL Added HCl 1 : 1 drop by drop until gladak gas stopped Diluted with water until the limit sign Shake until mixed perfectly Washed and filled with Na-EDTA solution 0,01 M Pipette with volume-tric pipette 50 mL of CaCl2 solution Entered into the Erlenmeyer 300 mL Added 5 mL of buffer solution pH 10 Added 5 drops of EBT indicator Titrated with Na-EDTA solution 0,01 M Stopped titration when theres changing color from redish grape to blue

Changing Color

Read and note the number on burette when the first and the end of titration Determine and note Na-EDTA solution that used in titration Calculated the mean concentration of Na-EDTA

The mean concentration of Na-EDTA

Before:CaCO3 powder:white

Aquades :colorless

HCl solution: colorless

Buffersolution:colorless

EBT Indicatior: dark purple (red wine)

Na-EDTA: colorless

After:CaCO3 solution: turbid

Buffer solution +CaCl2: colorless

Buffer solution +CaCl2+EBT: reddish grape

After titrated by Na-EDTA: reddish grape to blue

V1EDTA: 8 mLV2EDTA: 7.5 mLV3EDTA: 7.3 mLCaCO3(s)+H2O(l)CaCO3(aq) .

CaCO3(s)+2HCl(aq)CaCl2(aq)+CO2(g) + H2O(l)

Ca2++Y4- CaY2-

Na-EDTA concentration is 0.0106 M

25 mL of sample water2.Determination the hardness of well water

Pipette and dropped to Erlenmeyer Added 2 mL buffer solution pH 10 Added 3 drops of BET Titration with EDTA 3x

Blue (preciously until red color disappear)

Calculated the sum of the hardness in CaCO3 salt per liter of water (in the form of ppm)

The average hardness water of well water

Well water from kenjeran: colorless

Buffersolution:colorless

EBT Indicatior: dark purple (red wine)

Na-EDTA: colorless

After:Buffer solution +well water: colorless

Buffer solution +well water+EBT: reddish grape

After titrated by Na-EDTA: reddish grape to blue

V1EDTA:1. 8 mLV2EDTA: 2.2 mLV3EDTA: 2.0 mLThe total of hardness well water in kenjeran is 210.6 ppm

G. ANALYSIS AND DISCUSSION a. Determination of Standardization Na-EDTA 0,01 M with CaCO3 as primery standard solution.In the experiment that we have done, we used 0,081 grams of white powder CaCO3, then we poured into volumetric flask, then we add aquadest. The reaction that occur is : CaCO3(s) + H2O(l) CaCO3(aq) . After that we add HCl 6M, 1:1 drops by drops until the bubbles disappear (CO2 lose). And then we dilute with aquadest again until formed CaCl2 solution. The reaction that occur in this step is :CaCO3(s) + 2 HCl(aq) CaCl2(aq) + CO2(g) + H2O(l)To know that CO2 is lose we observe with there is changes from turbid become clear solution. After that we pipette 10 ml of CaCl2 solution 1ml of buffer solution. And we add 2 drops of EBT indicators. In the basic, this titration formed complex ions, Ca2+ with EDTA. EDTA is a chelating agent that can donate electrons (Lewis rule) which would then form a complex with the metal ion (Lewis acid). EDTA will first form a complex with Ca2 +. As in any titration we will need an indicator to determine when all the Ca 2 + has formed a complex with EDTA (endpoint).The metals will form complex with EDTA in different pH. Ca2+ react well in pH between 8 until 10.Forming of complex between metallic ions with EDTA depends on pH solution. In this titration we use EBT (Erichrome Black T). This indicator is include weak acid that have base 3 (H3In). Balancing of disotiation indicator will give different color and form complex 1:1 with amount of metallic ions, so it will give different color in the end of titration. The changes color in the titration is solution that contain metallic ions of Ca2+ after adding EBT is become red grape. Then after in the eqivalent point, between metallic ions of Ca2+ with EDTA can we observe from solution become blue and indicators in the form of HIn2-. The reaction in EBT indicator : H2In- Hin2- + H+Red blueWith metallic ion: Ca2+ so it become Ca2+ + Hin2-CaIn- + H+Red wineWith EDTA : CaIn- + H2Y2- CaH2Y2- CaH2Y + In3-Red WineIn3- + H2O HIn- + OH-BlueThen the solution titrated with Na-EDTA. We stopped where there is changes of color from red wine become blue. The reaction that occur is : Ca2+ + Y4- CaY2-The blue colorthatoccurdue totitrantisamixtureofMgY2- and Y4-. When themixture wasaddedtoa solutioncontainingCa2+,CaY2- themore-stablewill be formedby freeMg2+ toreactwiththe indicator(EBT)and-formred MgIn-.After thecalciumis usedin full,additionaltitrantchangeMgIn- and MgY2indicatorturnsintoablue HIn2-form. In this experiment we got Na-EDTA 8 ml, 7.5 ml, and 7.3 ml. Then we calculate molarity of Na-EDTA using formula mmol Na-EDTA = mmol CaCO3.The molarity of Na-EDTA that we get is 0,0101 M, 0,0108 M, 0,011 M and the average of Na-EDTA concentration is 0.0106 M.

b. Determining Total Hardness Of Well Water.In the determination total hardness of well water, pipette 10 mL of well water and moved into Erlenmeyer 250 mL, then add 1 mL of buffers solution pH 10 in the form of clear colorless solution and 2 drops of EBT indicator with the red grape color. Then titrated with Na-EDTA solution until the analyte solution changed color into blue. The change color into blue it show that the end point titration is reach . Repeat the experiment 3 times than we can get the average total hardness water .Using equation :mmol sample = mmol EDTA We got mmol well water sample which are used to determine the mass of Ca2+. Mass Ca2 obtained is used to determine the hardness of well water by divided mass of Ca2 (gr) and well water volume (sample volume)(l).So, by using that equation the hardness water we got are 190ppm, 230ppm, 212ppm and the average of the hardness water are 210.6 ppm.

H. CONCLUSIONBased on experiment that we have done, we can conclude that :1. Na-EDTA concentration is 0.0106 M2. The total of hardness well water in kenjeran is 210.6 ppmI. ANSWER OF QUESTIONMaking and Determining (standardization) of Na-EDTA solution. 1) Find the chemical formula of Na-EDTA, Black Eriokrom T!Answer: The chemical formula of Na-EDTA is

The chemical formula of Black Eriokrom T is

2) What is the concentration of CaCl2 solution if it is expressed with ppm CaCO3?Answer: CaCO3 + 2 HCl CaCl2 + H2O + CO2Mass CaCO3=0,081 gram=81,0 mgVolume CaCO3=100 mL=0,1 LConcentration of CaCO3 in ppm = ppm = ppm = 810 ppm

3) How to make buffer solution of ammonia + ammonia chloride with pH 10? Show the calculation!Answer: NH3 + HClNH4ClNH4OH + NH4Cl buffer

[OH-]=

=

=pH=14 pOH10=14 pOHpOH=4pOH=- log [OH-]4=- log [OH-][OH-]=10-4

10-4=

=

=

1,8 x 10-5=6,3 x 10-4 . V=gr supposed VNH4OH=1 Lso, gr=6,3 x 10-4 gram

=

=

Application of Complexometri Titration 1. Why the pH of a solution is the important factor in choosing indicator for complexiometry titration?Answer: The selection of indicators related to the use of pH, as required indicators that renponsif against pMg, pCa, PCU, and p the other, and because of the indicator should be releasing metal ions on EDTA at a pM value that is very close to pM values at the equivalence point.

2. A 100 mL of sample water containing ions Ca2+ and Mg 2+ is titrated with 15.28 mL of 0.01016 M EDTA in an ammonia buffer pH 10. Another example is 100 mL titrated with NaOH to precipitate Mg (OH)2 and then titrated to pH 13 with 10.43 mL of the same EDTA solution. Calculate how ppm CaCO3 and MgCO3 in the sample?Answer:Known : VEDTA 1 =15,28 mL MEDTA=0,01016 M VEDTA 2=10,43 mL(V1 V2) EDTA= 15,28-10,43=4,85 mLAsked :ppm CaCO3 dan ppm MgCO3Answered: ppm CaCO3mmol CaCO3=mmol EDTA=( M x V ) EDTA=0,01016 x 10,43=0,1059 mmolmg CaCO3=mmol x Mr=0,1059 x 100=10,59 mg

ppm CaCO3==105,9 mg/L

ppm MgCO3mmol MgCO3=mmol EDTA=[ M x (V1 V2)] EDTA=0,01016 x 4,85=0,0493 mmolmg MgCO3=mmol x Mr=0,0493 x 84=4,1412 mg

ppm MgCO3==41,412 mg/LJ. REFERENCEHusain, Asif. 2007. Theoritical Basis of Analysis Complexometric Titration. New Delhihttp://amrita.vlab.co.in/ Accessed on Monday, December 16th 2013http://en.wikipedia.org/wiki/Complexometric_titration, December 16th 2013 http://en.wikipedia.org/wiki/Water_well Accessed on Friday, 27th 2013 at 11.23http://en.wikipedia.org/wiki/Hard_water Accessed on Friday, 27th 2013 at 11.38Tim.2013.Panduan Praktikum Kimia Analitik I Dasar-Dasar Kimia Analitik. Surabaya:Jurusan Kimia FMIPA UNESA

K. ATTACHMENTPICTUREEXPLANATION

Detrmining Standarization Na-EDTA Solution 0.01M With CaCl2 As Primary Standard Solution

CaCl2 after adding by Erichrome Black T (EBT)

CaCl2 after titrated by Na-EDTA solution it change became blue

Determining total Hardness Water of Well Water

Well water after adding by (EBT) Erichrome Black T

Well Water after titrated by Na-EDTA solution it change became blue

L. CALCULATIONDetermining standardization Na-EDTA solution 0.01 with CaCl2 as primary standard solution.Known : mass of CaCO3=0.081 grvolume of CaCO3=10 mLV1EDTA= 8 mLV2EDTA=7.5 mLV3EDTA= 7.3 mLMr CaCO3 = 100V of CaCO3 dilution=100 mL=0.1Reaction :CaCO3(s) + 2 HCl(aq) CaCl2(aq) + CO2(g) + H2O(l)Ca2+ + Y4- CaY2-

Answer:M CaCO3=

1. At V EDTA 8 mLmmol CaCO3= mmol EDTAM1. V1 = M2.V2 0.0081 . 10 = M2 . 8 M2= 0.0101 M

2. At V EDTA 7.5 mLmmol CaCO3= mmol EDTAM1. V1 = M2.V2 0.0081 . 10 = M2 7.5 M2= 0.0108 M

3. At V EDTA7.3 mLmmol CaCO3= mmol EDTAM1. V1 = M2.V2 0.0081 . 10 = M2 . 7.3 M2= 0.011 M

Average of NA-EDTA Concentration =

Application of Complexometry Titration Known :M Na-EDTA=0.0106 MMr CaCO3 = 100Sample volume=10MlV1EDTA:1. 8 mLV2EDTA: 2.2 mLV3EDTA: 2.0 mLAnswer :1. At V EDTA 1.8 mLV Na-EDTA. M Na-EDTA = V Ca2+ . M Ca2+1.8. 0.0106 = 10 . M Ca2+M Ca2+= 1.9 x 10-3 Mass of Ca2+= mmol Ca2+x Mr CaCO3=1.9 x 10-3 x 1.0 x 10-2 x 100=1.9 x 10-3 g=1.9 mgHardness of well water =

2. At V EDTA 2.2 mLV Na-EDTA. M Na-EDTA = V Ca2+ . M Ca2+2.2. 0.0106 = 10 . M Ca2+M Ca2+= 2.3 x 10-3 Mass of Ca2+= mmol Ca2+x Mr CaCO3=2.3 x 10-3 x 1.0 x 10-2 x 100=2.3 x 10-3 g=2.3 mgHardness of well water =

3. At V EDTA 2.0 mLV Na-EDTA. M Na-EDTA = V Ca2+ . M Ca2+2.0. 0.0106 = 10 . M Ca2+M Ca2+= 2.12 x 10-3 Mass of Ca2+= mmol Ca2+x Mr CaCO3=2.12 x 10-3 x 1.0 x 10-2 x 100=2.12 x 10-3 g=2.12 mgHardness of well water =

The total average of hardness well water is =

The limit of tolerant hardness water is about 50-80 ppm and our hardness water is 210.6 ppm, so our hardness water is higher than the tolerant limit.Complexometry Titration 20