The concentration of a solution of EDTA was determined by standardizing against a solution of Ca2+ prepared from the primary standard CaCO3. A 0.4302g sample of CaCO3 was transferred to a 60mL volumetric flask, dissolved using a minimum of 6 M HCl solution, and diluted to volume. A 44mL portion of this solution was transferred into a 250-mL Erlenmeyer flask and the pH adjusted by adding 5 mL of a pH 10 NH3-NH4 L buffer containing a small amount of Mg2+ EDTA. After adding calmagite as a visual indicator, the solution was titrated with the EDTA, requiring 632mL to reach the end point. Calculate the molar concentration of the titrant

The concentration of a solution of EDTA was determined by standardizing against a solution of Ca2+ prepared from the primary standard CaCO3. A 0.4302g sample of CaCO3 was transferred to a 60mL volumetric flask, dissolved using a minimum of 6 M HCl solution, and diluted to volume. A 44mL portion of this solution was transferred into a 250-mL Erlenmeyer flask and the pH adjusted by adding 5 mL of a pH 10 NH3-NH4 L buffer containing a small amount of Mg2+ EDTA. After adding calmagite as a visual indicator, the solution was titrated with the EDTA, requiring 632mL to reach the end point. Calculate the molar concentration of the titrant

Fundamentals Of Analytical Chemistry

9th Edition

ISBN:9781285640686

Author:Skoog

Publisher:Skoog

Chapter17: Complexation And Precipitation Reactions And Titrations

Section: Chapter Questions

Problem 17.33QAP

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The concentration of a solution of EDTA was determined by standardizing against a solution of Ca2+ prepared from the primary standard CaCO3. A 0.4025 g sample of CaCO3 was transferred into a 250 mL Erlenmeyer flask and the pH adjusted by adding 5 mL of a pH 10 NH3-NH4Cl buffer containing a small amount of Mg2+EDTA. After adding calmagite as a visual indicator, the solution was titrated with the EDTA requiring 42.36 mL to reach the end point. Report the molar concentration of the titrant.
A 0.5745 g sample of an alloy containing principally bismuth and lead is dissolved in nitric acid and diluted to 250.0 mL in a volumetric flask. A 50.00 mL aliquot is withdrawn, the pH adjusted to 1.5, and the bismuth titrated with 30.26 mL of 0.01024 M EDTA. The pH of the solution is then increased to 5.0 and the lead titrated with 20.42 mL of the same EDTA solution. Calculate the percentages of lead and bismuth in the alloy.
To determine the concentration of an EDTA solution, the following magnesium(II) solution is prepared: metallic magnesium (m(Mg) = 0.5915 g) is dissolved in dilute sulfuric acid, the resulting solution is poured into a volumetric flask with a volume of 0.250 L and is filled to the graduation mark with water. The titration of an aliquot of magnesium(II) solution with a volume of 25.00 ml consumes (11.11 ml; 11.32 ml; 11.24 ml; 11.29 ml) of EDTA. Calculate the concentration of EDTA solution with accuracy corresponding to the starting data, give confidence interval.
An antacid tablet, weighing 1.25 g, was dissolved in a 1.0 L volumetric flask to allow for determination of calcium carbonate and magnesium carbonate contents. After preparing the solution, an aliquot of 10.0 ml was transferred to an Erlenmeyer flask containing a buffer solution with pH = 10. This aliquot was then titrated with EDTA 0.0040 mol/L and the average volume spent was 15.01 mL. To measure calcium after precipitation After the magnesium was fractionated, a second 10.00 mL aliquot of the stock solution was transferred to an Erlenmeyer flask. and the pH of the present solution was adjusted to a value of approximately 13. In EDTA titration, the volume consumed for observation of the end point was equal to 13.03 mL. Based on this information, (a) Outline the two steps involved, representing the related reactions. (b) Calculate the concentrations of CaCO3 and MgCO3 present in the initial solution. (c) Calculate the masses of CaCO3 and MgCO3 present in the pellet. (d) Calculate the…
. An antacid tablet, weighing 1.25 g, was dissolved in a 1.0 L volumetric flask to allow for determination of calcium carbonate and magnesium carbonate contents. After preparing the solution, an aliquot of 10.0 ml was transferred to an Erlenmeyer flask containing a buffer solution with pH = 10. This aliquot was then titrated with EDTA 0.0040 mol/L and the average volume spent was 15.01 mL. To measure calcium after precipitation. After the magnesium was fractionated, a second 10.00 mL aliquot of the stock solution was transferred to an Erlenmeyer flask, and the pH of the present solution was adjusted to a value of approximately 13. In EDTA titration, the volume consumed for observation of the end point was equal to 13.03 mL. Based on this information, a) Outline the two steps involved, representing the related reactions./5 b) Calculate the concentrations of CaCO3 and MgCO3 present in the initial solution./6 c) Calculate the masses of CaCO3 and MgCO3 present in the pellet./6 d) Calculate…
0.8153 g of a sample containing Pb(NO3)2 was taken, dissolved in water, and 40.20 mL of 0.06 M EDTA was added. What is the percentage of Pb(NO3)2 since the excess EDTA is back-titrated with 23.10 mL of 0.02 M EDTA? (Pb(NO3)2: 331 g/mol, Pb: 207 g/mol)
For the complexiometric titration of Ca2 + ions in the shell of the egg sample weighing 62,576 g, the necessary procedures were applied to the egg shells and 100 mL sample was prepared. 1 mL of the prepared sample was taken and diluted to 100 mL, the pH was adjusted, two drops of EBT indicator were dropped on it. The prepared solution was titrated with 23.6 mL of 0.0095 M EDTA solution. The amount of calcium in the sample is in terms of% CaCO3.
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A 0.9352g sample of ore containing Fe³+, Al³+ and Sr²+ was dissolved and made up to 500.00 mL. The analysis of metals was performed using complexation volumetry. Initially, an aliquot of 50.00 mL had its pH adjusted to 1.0 and titrated with a standard 0.03145 mol/L EDTA solution, requiring 6.95 mL to reach the end point. Subsequently, another 25.00 mL aliquot was buffered at pH=5 and titrated with the same EDTA solution, requiring 6.24 mL to reach the end point. Finally, a third aliquot of 25.00 mL was titrated at pH=11, requiring 11.10 mL of the same EDTA solution to complete the titration. Given the molar masses: Fe=55.845 g/mol; Al-26.982 g/mol and Sr-87.620 g/mol. a) Determine the percentage of each of the metals in the sample. b) Explain why the change in pH allows the determination of the three ions in this sample.
0.8153 g of a sample containing Pb(NO3)2 was taken, dissolved in water, and 40.20 mL of 0.06 M EDTA was added. If the excess EDTA was back-titrated with 23.10 mL of 0.02 M EDTA, which of the following is the percentage of Pb(NO3)2? (Pb(NO3)2: 331 g/mol, Pb: 207 g/mol) A. 85,23B. 38.25C. 35.63D. 79.17
A 1.509-g samle of a Pb/Cd alloy was dissolved in acid and diluted to exactly 250.0 mL in a volumetric flask. A 50.00-mL aliquot of the diluted solution was brought to a pH of 10.0 with an HCN/NaCN buffer, which also served to mask the Cd2+; 11.56mL of the EDTA solution were needed to titrate the Pb2+. Calculate the percentage of Pb and Cd in the sample.
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