What is the rationale of using EDTA as titrant and EBT as indicator for determining the hardness of water via titration? O a. The Kf of EDTA-metal complex is larger than Kf of EBT-metal complex; a color change is observed when EDTA displaced EBT EBT changes color from red to blue when the pH of the solution reaches 10 while EDTA selectively binds at a 1:1 ratio with most metals at pH 10 O b. O c. EBT reacts with EDTA once all of the metals in the sample is consumed resulting to a visible color change from red to blue O d. EBT selectively binds with Mg to form a red solution, once EDTA is added EBT then binds to Ca to form a blue solution

What is the rationale of using EDTA as titrant and EBT as indicator for determining the hardness of water via titration? O a. The Kf of EDTA-metal complex is larger than Kf of EBT-metal complex; a color change is observed when EDTA displaced EBT EBT changes color from red to blue when the pH of the solution reaches 10 while EDTA selectively binds at a 1:1 ratio with most metals at pH 10 O b. O c. EBT reacts with EDTA once all of the metals in the sample is consumed resulting to a visible color change from red to blue O d. EBT selectively binds with Mg to form a red solution, once EDTA is added EBT then binds to Ca to form a blue solution

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

Ethylenediaminetetraacetate (EDTA4 ) is used as a complexing agent in chemical analysis with the structure shown in Fig. 21.7. Solutions of EDTA4 are used to treat heavy metal poisoning by removing the heavy metal in the form of a soluble complex ion. The complex ion virtually prevents the heavy metal ions from reacting with biochemical systems. The reaction of EDTA4 with Pb2+ is Pb2+(aq) + EDTA4(aq) iPbEDTA2(aq) K = 1.1 1018 Consider a solution with 0.010 mol of Pb(NO3)? added to 1.0 L of an aqueous solution buffered at pH = 13.00 and containing 0.050 M Na1EDTA. Does Pb(OH)2 precipitate from this solution? [Ksp for Pb(OH)2 = 1.2 1015.
At 25C, 10.24 mg of Cr(OH)2 are dissolved in enough water to make 125 mL of solution. When equilibrium is established, the solution has a pH of 8.49. Estimate Ksp for Cr(OH)2.
Iron(III) is best determined by addition of excess EDTA, followed by back-titration with a metal ion that reacts rapidly with EDTA. A 700.0-mg sample is dissolved, 20.00 mL of 0.0500M EDTA is added, and the excess EDTA is titrated with 5.08 mL of 0.0420M copper(lI). Calculate the percentage of Fe,O, in the sample.
Which of the following statements regarding complexometric titrations is incorrect ? O The higher the ammonia concentration, the less sharper the end point for the EDTA-Zn²+ complex. O In the pH range 3-10 the predominant species are H2Y2- and HY3- O The larger the formation constant for the EDTA-metal complex, the sharper the end point. O a4 value is proportional to the pH value. O EDTA is a hexaprotic acid.
An alloy containing Ni, Fe and Cr was analyzed by a complexation titration using EDTA as titrant. A 0.7176 g sample of the alloy was dissolved in HNO3 and diluted to 250 mL in a flask. A 50.00 mL aliquot of the sample, treated with pyrophosphate to mask Fe and Cr, required 26.14 mL of 0.05831 M EDTA to reach the murexide endpoint. A second 50.00 mL aliquot was treated with hexamethylenetetramine to mask Cr and titration with 0.05831 M EDTA required 35.43 mL to reach the murexide endpoint. Finally, a third 50.00 mL aliquot was treated with 50.00 mL of 0.05831 M EDTA and titrated back to the murexide endpoint with 6.21 mL of 0.06316 M Cu(II). the weight percentages of Ni, Fe and Cr in the alloy.
At equivalent point, 25.00 mL of 0.10 M EDTA is required to titrate 50.00 mL of calcium in body fluid (buffered at pH 10). Calculate the concentration of calcium (in pCa). The K’f for complex CaY2- is 5.0 x 10^10.
The amount of chloride in a brine solution is determined by the Volhard method. 15 mL 0.1182 M standard AgNO3 solution was added to 10 mL of the solution. Excess silver was back titrated with 0.101 M standard KSCN solution and 2.38 mL KSCN was spent to reach the turning point where the red Fe(SCN)2+ complex was formed. Which of the following is the chloride concentration in the brine solution in g / L? (Cl: 35.5 g / mol) A) 5,44 B) 8,63 C) 2,89 D) 7,89
0.4545 g CaCO3 was dissolved in HCl and the resulting solution was diluted to 0.25 L. Twenty-five mL aliquot of this solution required 35.2 mL of EDTA upon performing titrimetric analysis. Determine the molarity of EDTA
20.54 The K, for the complex ion formation between Pb and EDTA' Pb + EDTA'- * Pb(EDTA)' is 1.0 X 10 at 25°C. Caleulate Pb ] at equilibrium in a solution containing 1.0 t10' M Pb and 2.0 x 10 MEDTA
EXAMPLE: Chromium(III) is slow to react with EDTA (H4Y) and is therefore determined by back-titration. A pharmaceutical preparation containing chromium(III) is analyzed by treating a 2.63g sample with 5mL of (0.0103M) EDTA. Following reaction, the unreacted EDTA is back-titrated with 1.32mL of (0.0112M) zinc solution. What is the percent chromium chloride in the pharmaceutical preparation?
Determinethe concentration of an EDTA solution given that a 20.00 mLsample of 0.02491M Zn2+was titrated with37.84mL of EDTA
1.Solution of EDTA is particularly valuable as titrants because the reagent combines with metal ions in a 1:1 ratio regardless of the charge on the cation. For example, Fe(ll) and Fe(lll), complexes are formed with EDTA with great stability. The formation constants for the Fe(ll)-EDTA chelate, and Fe(lll)-EDTA chelate are 2.1 × 1014 and 1.3 × 1025, respectively. a) For each ion complex mentioned above, write the equations of reactions for complex formation and expression for the complex formation constant. b) Calculate the concentration of Fe3+ in a solution that was prepared by mixing 50.0 mL of 0.200 M Fe3+ with 200,0 m of 0.0100 M EDTA. The mixture was buffered to a pH of 11.00. (Given the value of a, = 0.85 at pH 11.00)