Edta titration virtual lab

Edta titration virtual lab DEFAULT




  • Under the chemical content, select the tests- Hardness, Alkalinity or COD.


a. Determination of Hardness of Water Sample


  1. Select the titrant.
  2. Adjust the speed of the drops from the burette.
  3. Adjust the molarity of titrant.
  4. Select a definite volume of water sample.
  5. Choose the indicator & start the titration.
  6. When colour changes from wine red to blue click the "stop" button & note the volume of EDTA used.
  7. Then calculate the hardness of water sample in ppm using the equation as follows.

 «math xmlns=¨http://www.w3.org/1998/Math/MathML¨»«mi»T«/mi»«mi»o«/mi»«mi»t«/mi»«mi»a«/mi»«mi»l«/mi»«mo»§nbsp;«/mo»«mi»h«/mi»«mi»a«/mi»«mi»r«/mi»«mi»d«/mi»«mi»n«/mi»«mi»e«/mi»«mi»s«/mi»«mi»s«/mi»«mo»§nbsp;«/mo»«mi»a«/mi»«mi»s«/mi»«mo»§nbsp;«/mo»«mi»C«/mi»«mi»a«/mi»«mi»C«/mi»«msub»«mi»O«/mi»«mn»3«/mn»«/msub»«mo»§nbsp;«/mo»«mo»(«/mo»«mi»p«/mi»«mi»p«/mi»«mi»m«/mi»«mo»)«/mo»«mo»=«/mo»«mfrac»«mrow»«mi»V«/mi»«mi»o«/mi»«mi»l«/mi»«mo».«/mo»«mo»§nbsp;«/mo»«mi»o«/mi»«mi»f«/mi»«mo»§nbsp;«/mo»«mi»E«/mi»«mi»D«/mi»«mi»T«/mi»«mi»A«/mi»«mo»(«/mo»«mi»m«/mi»«mi»L«/mi»«mo»)«/mo»«mo»§#215;«/mo»«mn»0«/mn»«mo».«/mo»«mn»1«/mn»«mo»§#215;«/mo»«mi»m«/mi»«mi»o«/mi»«mi»l«/mi»«mi»a«/mi»«mi»r«/mi»«mi»i«/mi»«mi»t«/mi»«mi»y«/mi»«mo»§nbsp;«/mo»«mi»o«/mi»«mi»f«/mi»«mo»§nbsp;«/mo»«mi»E«/mi»«mi»D«/mi»«mi»T«/mi»«mi»A«/mi»«mo»§#215;«/mo»«msup»«mn»10«/mn»«mn»6«/mn»«/msup»«/mrow»«mrow»«mi»V«/mi»«mi»o«/mi»«mi»l«/mi»«mo».«/mo»«mo»§nbsp;«/mo»«mi»o«/mi»«mi»f«/mi»«mo»§nbsp;«/mo»«mi»t«/mi»«mi»h«/mi»«mi»e«/mi»«mo»§nbsp;«/mo»«mi»s«/mi»«mi»a«/mi»«mi»m«/mi»«mi»p«/mi»«mi»l«/mi»«mi»e«/mi»«mo»§nbsp;«/mo»«mo»(«/mo»«mi»m«/mi»«mi»L«/mi»«mo»)«/mo»«/mrow»«/mfrac»«/math»

Observations And Calculations:


NoVol. of the sample (mL)Burette Reading (mL)Vol.of EDTA (mL)
 Initial Final


Volume of EDTA used=..................mL.

Molarity of EDTA =..................M.

Volume of the water sample =..................mL.

Therefore the total hardness of the sample is = «math xmlns=¨http://www.w3.org/1998/Math/MathML¨»«mfrac»«mrow»«mi»V«/mi»«mi»o«/mi»«mi»l«/mi»«mo».«/mo»«mo»§nbsp;«/mo»«mi»o«/mi»«mi»f«/mi»«mo»§nbsp;«/mo»«mi»E«/mi»«mi»D«/mi»«mi»T«/mi»«mi»A«/mi»«mo»(«/mo»«mi»m«/mi»«mi»L«/mi»«mo»)«/mo»«mo»§#215;«/mo»«mn»0«/mn»«mo».«/mo»«mn»1«/mn»«mo»§#215;«/mo»«mi»m«/mi»«mi»o«/mi»«mi»l«/mi»«mi»a«/mi»«mi»r«/mi»«mi»i«/mi»«mi»t«/mi»«mi»y«/mi»«mo»§nbsp;«/mo»«mi»o«/mi»«mi»f«/mi»«mo»§nbsp;«/mo»«mi»E«/mi»«mi»D«/mi»«mi»T«/mi»«mi»A«/mi»«mo»§#215;«/mo»«msup»«mn»10«/mn»«mn»6«/mn»«/msup»«/mrow»«mrow»«mi»V«/mi»«mi»o«/mi»«mi»l«/mi»«mo».«/mo»«mo»§nbsp;«/mo»«mi»o«/mi»«mi»f«/mi»«mo»§nbsp;«/mo»«mi»t«/mi»«mi»h«/mi»«mi»e«/mi»«mo»§nbsp;«/mo»«mi»s«/mi»«mi»a«/mi»«mi»m«/mi»«mi»p«/mi»«mi»l«/mi»«mi»e«/mi»«mo»§nbsp;«/mo»«mo»(«/mo»«mi»m«/mi»«mi»L«/mi»«mo»)«/mo»«/mrow»«/mfrac»«/math» =.................ppm.




Total Hardness of the water sample = ..................ppm.



b. Determination of Alkalinity of Water Sample.

  1. Select the titrant.
  2. Select the normality.
  3. Adjust the speed of the drops from the burette.
  4. Select the titrate & choose a definite volume of the water sample.
  5. Select the indicator, phenolphthalein to get a pink colour.
  6. Stop titration when the solution becomes colourless & calculate phenolphthalein alkalinity (PA) as CaCO3 (mg/L) using the equation. Let A is the volume of titrant (mL) used in the titration (V1).
  7. Add methyl orange to the same flask & continue titration till the colour changes from yellow to orange. The total volume of titrant corresponds to total alkalinity (TA) as CaCO3 (mg/L). Let B is the total volume of titrant (mL) consumed with both the indicators (V2).


Observations and Calculations:


NoVol. of the sample (mL)Burette Reading (mL)Vol.of HCl (mL)
 Initial Final
1  (A) 
2  (B) 



Volume of HCl corresponding to phenolphthalein end point  (A)=..................mL.

Normality of acid =..................N

Volume of the water sample =..................mL.

Normality of water corresponding to phenolphthalein end point =«math xmlns=¨http://www.w3.org/1998/Math/MathML¨»«mo»§nbsp;«/mo»«mo»(«/mo»«mi»P«/mi»«mi»A«/mi»«mo»)«/mo»«mo»=«/mo»«mo»§nbsp;«/mo»«mfrac»«mrow»«mi»A«/mi»«mo»§#215;«/mo»«mi»N«/mi»«mi»o«/mi»«mi»r«/mi»«mi»m«/mi»«mi»a«/mi»«mi»l«/mi»«mi»i«/mi»«mi»t«/mi»«mi»y«/mi»«mo»§nbsp;«/mo»«mi»o«/mi»«mi»f«/mi»«mo»§nbsp;«/mo»«mi»a«/mi»«mi»c«/mi»«mi»i«/mi»«mi»d«/mi»«mo»§#215;«/mo»«mn»50«/mn»«mo»,«/mo»«mn»000«/mn»«/mrow»«mrow»«mi»V«/mi»«mi»o«/mi»«mi»l«/mi»«mi»u«/mi»«mi»m«/mi»«mi»e«/mi»«mo»§nbsp;«/mo»«mi»o«/mi»«mi»f«/mi»«mo»§nbsp;«/mo»«mi»s«/mi»«mi»a«/mi»«mi»m«/mi»«mi»p«/mi»«mi»l«/mi»«mi»e«/mi»«mo»§nbsp;«/mo»«mo»(«/mo»«mi»m«/mi»«mi»L«/mi»«mo»)«/mo»«/mrow»«/mfrac»«/math» =..................ppm.

Volume of HCl corresponding to methyl orange end point  (B)=..................mL.

Normality of acid =..................N

Volume of the water sample =..................mL.

Normality of water corresponding to methyl orange end point =«math xmlns=¨http://www.w3.org/1998/Math/MathML¨»«mo»§nbsp;«/mo»«mo»(«/mo»«mi»T«/mi»«mi»A«/mi»«mo»)«/mo»«mo»=«/mo»«mo»§nbsp;«/mo»«mfrac»«mrow»«mi»B«/mi»«mo»§#215;«/mo»«mi»N«/mi»«mi»o«/mi»«mi»r«/mi»«mi»m«/mi»«mi»a«/mi»«mi»l«/mi»«mi»i«/mi»«mi»t«/mi»«mi»y«/mi»«mo»§nbsp;«/mo»«mi»o«/mi»«mi»f«/mi»«mo»§nbsp;«/mo»«mi»a«/mi»«mi»c«/mi»«mi»i«/mi»«mi»d«/mi»«mo»§#215;«/mo»«mn»50«/mn»«mo»,«/mo»«mn»000«/mn»«/mrow»«mrow»«mi»V«/mi»«mi»o«/mi»«mi»l«/mi»«mi»u«/mi»«mi»m«/mi»«mi»e«/mi»«mo»§nbsp;«/mo»«mi»o«/mi»«mi»f«/mi»«mo»§nbsp;«/mo»«mi»s«/mi»«mi»a«/mi»«mi»m«/mi»«mi»p«/mi»«mi»l«/mi»«mi»e«/mi»«mo»§nbsp;«/mo»«mo»(«/mo»«mi»m«/mi»«mi»L«/mi»«mo»)«/mo»«/mrow»«/mfrac»«/math» =..................ppm.


Result of Titration

OH alkalinity as CaCO3

CO3 alkalinity as CaCO3

HCO3 alkalinity as CaCO3

PA = 0




PA < 1/2TA



TA - 2PA

PA = 1/2TA




PA > 1/2TA

2PA - TA

2(TA - PA)








Alkalinity is due to............ =..............ppm.


c. Determination of COD of water sample


  1. Select the water sample.
  2. To reflux the contents in the RB flask click the "switch on mantle" button.
  3. Click "start titration" to titrate the contents.
  4. Select the normality of ferrous ammonium sulphate (FAS).
  5. Start titration & note the volume of titrant consumed when colour changes from bluish green to wine red. (Let the volume of titrant  be VmL).
  6. Repeat the same with the blank (Let the volume of the titrant be V1mL).
  7. COD calculated using the equation.

 «math xmlns=¨http://www.w3.org/1998/Math/MathML¨»«mi»C«/mi»«mi»O«/mi»«mi»D«/mi»«mo»§nbsp;«/mo»«mo»(«/mo»«mfrac»«mrow»«mi»m«/mi»«mi»g«/mi»«/mrow»«mi»L«/mi»«/mfrac»«mo»)«/mo»«mo»=«/mo»«mfrac»«mrow»«mi»V«/mi»«mi»o«/mi»«mi»l«/mi»«mo».«/mo»«mi»F«/mi»«mi»A«/mi»«mi»S«/mi»«mo»§nbsp;«/mo»«mi»f«/mi»«mi»o«/mi»«mi»r«/mi»«mo»§nbsp;«/mo»«mi»s«/mi»«mi»a«/mi»«mi»m«/mi»«mi»p«/mi»«mi»l«/mi»«mi»e«/mi»«mo»§#215;«/mo»«mi»N«/mi»«mi»o«/mi»«mi»r«/mi»«mi»m«/mi»«mi»a«/mi»«mi»l«/mi»«mi»i«/mi»«mi»t«/mi»«mi»y«/mi»«mo»§nbsp;«/mo»«mi»o«/mi»«mi»f«/mi»«mo»§nbsp;«/mo»«mi»F«/mi»«mi»A«/mi»«mi»S«/mi»«mo»§#215;«/mo»«mn»8000«/mn»«/mrow»«mrow»«mi»V«/mi»«mi»o«/mi»«mi»l«/mi»«mo».«/mo»«mo»§nbsp;«/mo»«mi»o«/mi»«mi»f«/mi»«mo»§nbsp;«/mo»«mi»s«/mi»«mi»a«/mi»«mi»m«/mi»«mi»p«/mi»«mi»l«/mi»«mi»e«/mi»«/mrow»«/mfrac»«/math»



Observations And Calculations:


SampleNOVol. of sample (mL)Burette Reading (mL)Vol.of FAS (mL)


Volume of FAS used= (V1-V2) =..................mL.

Normality of FAS =..................N.

Volume of the water sample =..................mL.

Therefore COD of the water sample = «math xmlns=¨http://www.w3.org/1998/Math/MathML¨»«mfrac»«mrow»«mi»V«/mi»«mi»o«/mi»«mi»l«/mi»«mo».«/mo»«mi»F«/mi»«mi»A«/mi»«mi»S«/mi»«mo»§nbsp;«/mo»«mi»f«/mi»«mi»o«/mi»«mi»r«/mi»«mo»§nbsp;«/mo»«mi»s«/mi»«mi»a«/mi»«mi»m«/mi»«mi»p«/mi»«mi»l«/mi»«mi»e«/mi»«mo»§#215;«/mo»«mi»N«/mi»«mi»o«/mi»«mi»r«/mi»«mi»m«/mi»«mi»a«/mi»«mi»l«/mi»«mi»i«/mi»«mi»t«/mi»«mi»y«/mi»«mo»§nbsp;«/mo»«mi»o«/mi»«mi»f«/mi»«mo»§nbsp;«/mo»«mi»F«/mi»«mi»A«/mi»«mi»S«/mi»«mo»§#215;«/mo»«mn»8000«/mn»«/mrow»«mrow»«mi»V«/mi»«mi»o«/mi»«mi»l«/mi»«mo».«/mo»«mo»§nbsp;«/mo»«mi»o«/mi»«mi»f«/mi»«mo»§nbsp;«/mo»«mi»s«/mi»«mi»a«/mi»«mi»m«/mi»«mi»p«/mi»«mi»l«/mi»«mi»e«/mi»«/mrow»«/mfrac»«/math» =..............ppm.




COD of water sample =....................ppm.


Points to Remember while Performing the Experiment in a Real Laboratory:


  1. Always wear lab coat and gloves when you are in the lab. When you enter the lab, switch on the exhaust fan and make sure that all the chemicals and reagents required for the experiment are available. If it is not available, prepare the reagents using the components for reagent preparation.
  2. Properly adjust the flame of the Bunsen burner. The proper flame is a small blue cone; it is not a large plume, nor is it orange.
  3. Make sure to clean all your working apparatus with chromic acid and distilled water and ensure that all the apparatus are free from water droplets while performing the experiment.
  4. Make sure to calibrate the electronic weigh balance before taking the measurements.
  5. Clean all glass wares with soap and distilled water. Once the experiment completed recap the reagent bottles. Switch off the light, exhaust fan and Gas cylinder before leaving the lab.
  6. Discard the used gloves in a waste bin.


Cite this Simulator:

Sours: https://vlab.amrita.edu/index.php?sub=2&brch=193&sim=1548&cnt=2

Water hardness is due to the presence of multivalent metal ions. In natural waters, the most abundant ions are calcium(II) and, in less amount, magnesium(II). Cations such as Fe(III), Al(III), Mn(II) and other metal ions also contribute to hardness, although their concentration level is much below the concentration level of calcium. Water hardness is a parameter of interest in water analysis, since it has adverse consequences in a great deal of human activities related to the use of this natural resource. The most widely employed assay for water hardness is complexometry. When hardness in water is determined by complexometry, the obtained value accounts for all multivalent metal ions present in the sample. Very often, the result is given as calcium carbonate equivalent per liter. In this simulated lab experiment, the complexometric titration of hardness in a water sample is carried out. All steps of the titration are covered, from the weighing of the titrant (EDTA as disodic salt) to the final calculation of the hardness parameter. The analyst can titrate the sample several times and enter the obtained values of the calculated mg/L of calcium carbonate equivalent for each titration. A final table shows and compares both the values calculated by the system and those calculated and entered by the analyst. An introduction shows the chelating properties of EDTA and a simulation of the the theoretical background of the titration is presented.

water analysis; water hardness; Ca and Mg in natural waters; complexometry; complexometric titration; EDTA; water hardness by complexometry; water hardness assay; eriochrome black T; interactive lab experiment; simulated determination of water hardness

Attribution-NonCommercial-NoDerivs 3.0 Unported

Esta obra está bajo una Licencia Creative Commons Attribution-NonCommercial-NoDerivs 3.0 Unported

Sours: https://rodin.uca.es/xmlui/handle/10498/14127?locale-attribute=es
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This video explains the procedure of a titration, a quantitative method to determine the concentration of an unknown solution. There are different sorts of titration, the acid-base titration, which is often performed during early semesters, or the complexometric titration to determine the cationic concentration of aqueous solutions.

To perform the titration a burette with calibrated milliliter scale is fastened using a burette clamp. In addition to this, a magnetic stirrer is used to ensure the mixing of the solution. Whenever performing a quantitative experiment it is important to work precisely, e.g. a volumetric pipette should be used to measure liquids in order to keep errors to a minimum.

The substance used to titrate has a well known concentration and by determining the amount of substance needed, the concentration of the unknown solution can be calculated. To illustrate the process, an acid-base titration is performed, where an acid of unkown concentration is titrated using a base of known concentration.

The burette is filled with caustic soda using a funnel, which has to be removed afterwards to prevent it from distorting the scale of the burette. The meniscus is lowered to match 0 on the scale and the excessive caustic soda is collected in a beaker. Afterwards the beaker is substituted with a clean beaker. 10 mL of the sample are poured into the beaker using a volumetric pipette.

A digital pH-meter or an indicator can be used to monitor the pH-value of a acid-base titration. An indicator can change its color according to the pH-value of the solution. In this example phenolphthalein and a pH-meter is used to monitor the pH-value.

The electrode of the pH-meter is stored in a cap filled with a solution of potassium chloride and should never run dry. Therefore it should be stored in a liquid if not used, preferably in a solution of potassium chloride. Before calibrating or using the electrode it has to be rinsed with demineralized water. To calibrate the electrode, it is plunged into a solution of pH-value 4 and the same value has to be set on the pH-meter. Afterwards it is rinsed and calibrated again using a solution of pH-value 7. Now the electrode can be fastened to the apparatus. Demineralized water can be added to the solution to ensure the electrode plunges in deep enough without touching the magnetic stirrer. After adding a few drops of phenolphthalein the titration can start.

The magnetic stirrer is turned on and the base can be added in sections of 1 mL. A pause after adding some base is necessary to reach the equilibrium of the acid-base reaction. When repeating the titration, the chunks around the endpoint have to be scaled down in order to determine the endpoint accurately.

The increase of the pH-value can be monitored using the pH-meter. In addition to this, the indicator will remain colored for a short amount of time when approaching the endpoint. After reaching the endpoint, the indicator is colored permanently. A small drop of base is sufficient to increase the pH-value by a considerable amount and therefore cause the indicator to change color.

The amount of acid in the solution of unknown concentration is equal to amount of base used to reach the endpoint and can be calculated. Principally multiple titrations should be performed to reduce errors.

Sours: http://www.stalke.chemie.uni-goettingen.de/virtuelles_labor/basics/2_more_en.html
Lab 17 - Titration (A/E Chem Virtual Lab)


Lab edta titration virtual




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