Regarding EDTA titrations and other complex forming reactions, indicate T or F 1) The relevant scientific terminology seems violent as it talks about teeth and claws 2) EDTA surrounds a metal from 8 points, forming an octahedral cage 3) The indicators in EDTA titration have one color when complexed with EDTA and another color when uncomplexed 4) The metal-EDTA complex must have a greater association constant than that of the metal indicator constant for the indicator to work 5) Only a few metals with very high complexation constants can be titrated with EDTA in acid solution

Regarding EDTA titrations and other complex forming reactions, indicate T or F 1) The relevant scientific terminology seems violent as it talks about teeth and claws 2) EDTA surrounds a metal from 8 points, forming an octahedral cage 3) The indicators in EDTA titration have one color when complexed with EDTA and another color when uncomplexed 4) The metal-EDTA complex must have a greater association constant than that of the metal indicator constant for the indicator to work 5) Only a few metals with very high complexation constants can be titrated with EDTA in acid 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

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A 100-mL sample of hard water is titrated with the EDTA solution in Problem 2. The same amount of Mg2 is added as previously, and the volume of EDTA required is 31.84 mL. a. What volume of EDTA is used in titrating the Ca2 in the hard water? _____________mL b. How many moles of EDTA are there in that volume? _____________ moles c. How many moles of Ca2 are there in the 100 mL of water? _____________ moles d. If the Ca2 comes from CaCO3, how many moles of CaCO3 are there in one liter of the water? How many grams of CaCO3 are present per liter of the water? _____________ mol / L _____________ g / L e. If 1 ppm CaCO3 = 1 mg per liter, what is the water hardness in ppm CaCO3? _____________ ppm CaCO3
Which of the following statements is TRUE about EDTA titration? A. Eriochrome black T is a titrant in EDTA titration B. EDTA titration can be used in the quantification of metals. C. EDTA titration is pH independent D. EDTA gives a sharper endpoint compared to a unidentate ligand. E. EDTA combines with metal in 1:6 ratio.
Which is NOT true about EDTA? a. EDTA acts as a complexing agent in compleximetric titrations b. EDTA acts as a lewic acid in formation of complexes c. EDTA forms a 1:1, stable, water-soluble complex d. EDTA has high formation constants with metals.
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
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.
The following statements are ways to mitigate EDTA titration's low sensitivity EXCEPT A. Buffer at specific pH to avoid other metal ions to complex with EDTA B. Use of masking agents to react with other cations C. Using higher concentration of EDTA titrant D. Use of optimal form of EDTA that will complex with the target metal ion/s E. None of the choices.
a. What is the structure and full name for EDTA? b. The titration of Zn^+2 and EDTA is carried out in the same manner as the Mg^+2 * EDTA titration (in fact, Zn metal may be used to standardize your EDTA solution). In this case, the ammonia from the pH 10 buffer serves an additional purpose. What is it? c. Although EDTA has, in its fully protonated form, 4 hydrogen atoms that can be lost, it is listed as a hexadentate ligand. Explain why this is the case.
Chromel is an alloy composed of nickel, iron and chromium.A 0.6472 g sample was dissolved and diluted to 250 mL. When a50 mL aliquot of 0.05182 M EDTA was mixed with an equal volumeof the diluted sample and all the three ions were chelated, a 5.11 mLback titration with 0.06241 M copper (II) was required.The chromium in a second 50 mL aliquot was masked through theaddition of hexamethylenetetramine, titration of the Fe and Nirequired 36.28 mL of 0.05182 M EDTA.Iron and chromium were masked with pyrophosphate in a third50 mL aliquot and the nickel was titrated with 25.91 mL of theEDTA solution.Calculate the percentage of nickel, chromium and iron in thealloy.
Calculate the % Copper in the alloy using the average titration vallue. given:Devarda alloy= 0.518g [EDTA] = 0.02 mol•dm^3 average titration number= 6.84cm^3
Which of the following statements about the indicators used in Edta titrations is false?A. The strength of the complex made with the metal ion should be less than the complex of the same metal with EDTA.B. Metal indicators are used to determine the turning point in complexometric titrations.C. They should form water-soluble colored chelate complexes with metals.D. The complex formation constant of the complex made with metal ions must be very low.
11.Residual EDTA titrations are employed in the analysis of Bi and ________ containing compounds. 12.The equilibrium constant that drives complexation reactions to completion is known as?
A. Calgon conditioning can be done by____________________________.B. The colour of metal-EBT complex is ___________________________ .C. If P is less than half M (or T) then alkalinity is due to _____________________.D. Hydroxide alkalinity is determined by ____________________ indicator.E. If sample water contains Mg(HCO3)2 = 14.6 mg/lit, Ca(HCO3)2 = 16.2 mg/lit, MgCO3 = 8.4mg/lit. The temporary hardness present per litre of the sample is__________________.