In complexation volumetry, classify the statements below as true or false. Justify the one(s) that you judge to be “false”. a) When preparing an EDTA solution, to be used as a titrant of Ca2+ ions, it is necessary to add a small amount of Mg2+ in the solution. b) A metallochromic (Ind) indicator is a substance that forms colored complexes with metallic ions. The colors of these complexes are always the same as the colors of the free forms of these indicators. c) In order for the titration of a metal (Me) with EDTA to be carried out, it is necessary that the Me-EDTA complex has a stability constant greater than that of the Me-Ind complex. d) In determining the partial hardness of a hard water sample with EDTA solution, murexide is used as an indicator at pH 10.

In complexation volumetry, classify the statements below as true or false. Justify the one(s) that you judge to be “false”. a) When preparing an EDTA solution, to be used as a titrant of Ca2+ ions, it is necessary to add a small amount of Mg2+ in the solution. b) A metallochromic (Ind) indicator is a substance that forms colored complexes with metallic ions. The colors of these complexes are always the same as the colors of the free forms of these indicators. c) In order for the titration of a metal (Me) with EDTA to be carried out, it is necessary that the Me-EDTA complex has a stability constant greater than that of the Me-Ind complex. d) In determining the partial hardness of a hard water sample with EDTA solution, murexide is used as an indicator at pH 10.

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

See similar textbooks

Similar questions

Sometimes it is not possible to indicate the end point of a titration.a) How can one proceed then and what is the name of the type of titration that can be performed? Briefly describe. An example in which this method can be used is in the determination of mercury, which forms strong complexes with EDTA, but for which there is no suitable indicator that can indicate the end point. b) You are given the task of determining the Hg2 + concentration in a sample solution? After adding an excess of EDTA, the sample solution is titrated with a magnesium solution. 20.00 ml of a 0.0452 M EDTA solution was added to 30.00 ml of sample solutionThe excess EDTA was determined by adding 0.0500 M Mg 2+ solution, consuming 4.37 ml to the end point.
If an unknown consisted of Co+2, Fe+2, Sr+2, or Ni+2, which cation would completely complex with EDTA first? Second? Third? Also, what are the minimum pH values for satisfactory titrations of the above metal cations?
Hardness in groundwater is due to the presence of metal ions, primarily Mg2+and Ca2+. Hardness is generally reported asppm (mg/L) CaCO3or mmol/L Ca2+. To measure water hardness, a sample of groundwater is titrated with EDTA, a chelating agent, in the presence of the indicator eriochrome black T, symbolized here as In. Eriochrome black T, a weaker chelating agent than EDTA, is red in the presence of Ca2+and turns blue when Ca2+is removed. A 50.00-mL sample of groundwater is titrated with 0.0850M EDTA. Assume that Ca2+accounts for all of the hardness in the groundwater. If 10.10 mL of EDTA is required to titrate the 50.00-mL sample, what is the hardness of the groundwater in molarity Ca2+and in ppm CaCO3?
EDTA is one of the common reagents used in a complexometric titration.a. Can we use EDTA titrations to determine the concentration of halides in a sample? Givereason for your answer.b. Why is EDTA used to determine concentration of a metal ion in a solution. c. Why is Erichrome black -T used as the indicator in EDTA titrations ?d. Explain hardness of water. Why is it usually expressed in terms of Ca2+ ions?
As part of a geological team that studied a local cave, you brought with you a bunch of 1.00 g rock samples to be studied. Each rock was prepared and titrated against 0.050 M EDTA. a. Calculate the percent calcite (CaCO3) content of rock A if it was titrated with 48.0 mL EDTA
In order to adjust the EDTA solution, 10 mL of 0.01M Ca + 2 sample was taken and 10 mL of pH 10 buffer was added on it and it was completed to 100 mL. Then, two drops of EBT indicator were added and titrated with EDTA. Since the consumption is 13 mL, what is the concentration of EDTA solution in terms of molarity?
The titration of Zn+2 and EDTA is carried out in the same manner as the Mg+2-EDTA titration. In this case, the ammonia in the EDTA buffer serves an additional purpose, what is it?
Janine's research focuses on the ability of quercetin, a flavonoid and natural dye, to detect the presence of Co2+ in wastewater samples. She prepared a set of calibration standard solutions by adding an excess of quercetin to solutions of varying Co2+ concentration and maintaining it at pH 6.4 using a Tris-HCl buffer. The reaction yields a colored complex solution that has a maximum absorbance at 440 nm:Co2+ + 2 Quercetin --> Co(Quercetin)22+ The absorbance measurements for the calibration solutions prepared are shown in the tables; a cuvette with a 2.50 cm path length was used. [Co2+], in M Absorbance Color Wavelength range (nm) 0.05 0.100 Red 625-740 0.10 0.166 Orange 590-625 0.20 0.285 Yellow 565-590 0.30 0.367 Green 490-565 0.40 0.454 Blue 440-490 0.50 0.571 Violet 380-440 Part of her research is to determine the extent of Co2+ pollution in a stream near a pharmaceutical company. She obtained a 50.0-mL sample of the stream water and buffered it to pH 6.4. She…
Which of the following statements is true regarding permanganimetry? a) Permanganate solution can oxidize water which is catalyzed by the presence of manganese dioxide or manganese ion. b) The light pink endpoint color for permanganimetry tends to fade with time due to the catalytic reaction. c) Standardization of the permanganate titrant is carried out at elevated temperature with sodium oxalate. d) all of these e) none of these
For complexometric titration of Ca (II) ions in the shell of an egg sample weighing 59,427 g, the necessary processes were applied to the egg shells and a sample of 100 mL was prepared. From the prepared sample, 1 mL was taken and diluted to 100 mL, the pH was adjusted, and two drops of EBT indicator were dripped on it. The prepared solution was titrated with 27.4 mL of EDTA solution set at 0.0097 M. Calculate the amount of calcium in the sample in CaCO3%. (Ca = 40g / mol, CaCO3= 100g / mol)
In order to adjust the EDTA solution, 10 mL of 0.01M Ca + 2 sample was taken and 10 mL of pH 10 buffer was added on it and it was completed to 100 mL. Then, two drops of EBT indicator were added on it and titrated with EDTA. Since the consumption is 13 mL, which of the following is the concentration of the EDTA solution in terms of molarity? A. 0.0076B. 0.0101C. 0.0067D. 0.0111
At pH 7, what metal ions can be titrated by EDTA?