At what pH does EDTA become a strong complexing agent? * 04 06 8 10 Which best describes the characteristic of an indicator in a direct EDTA titration? Binds with the ligand and changes color when freed Binds with the metal and changes color when freed Changes color when binding with the complex formed The ligand itself is the indicator Which of the following does NOT form a 1:1 ratio with an EDTA molecule? * Li Mg Bi Al

At what pH does EDTA become a strong complexing agent? * 04 06 8 10 Which best describes the characteristic of an indicator in a direct EDTA titration? Binds with the ligand and changes color when freed Binds with the metal and changes color when freed Changes color when binding with the complex formed The ligand itself is the indicator Which of the following does NOT form a 1:1 ratio with an EDTA molecule? * Li Mg Bi Al

Appl Of Ms Excel In Analytical Chemistry

2nd Edition

ISBN:9781285686691

Author:Crouch

Publisher:Crouch

Chapter9: Complexometric And Precipitation Titrations

Section: Chapter Questions

Problem 1P

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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.
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__________________.
Zinc on forms a 1:1 complex with a ligand called triethylenetetraamine. The formation constant for this complex is 1012. Calculate the [Zn2+] in a 0.01 M solution of the complex.
Determinethe concentration of an EDTA solution given that a 20.00 mLsample of 0.02491M Zn2+was titrated with37.84mL of EDTA
An unknown salt X reacts with hot conc. H2SO4 to produce a brown coloured gas which intensifies on addition on copper turnings. On adding dilute ferrous sulphate solution to an aqueous solution of X and then carefully adding conc. H2SO4along the sides of the test tube, a brown complex Y is formed at the interface between the solution and H2SO4. Identify X andY and write the chemical equation involved in the reaction.
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.
A 2.02.0 mL aliquot of 0.001 M NaSCNNaSCN is diluted to 30.030.0 mL with 0.2 M Fe(NO3)3Fe(NO3)3 and 0.1 M HNO3.HNO3. How many moles of SCN−SCN− are present? If all the SCN−SCN− is complexed with Fe3+Fe3+ to form FeSCN2+,FeSCN2+, what is the molar concentration of FeSCN2+?
Predict the structures of the metal-ligand bonding when SCN– reacts with Fe 2+ to form the bright red Fe(SCN)2+ ion. respond in terms of HSAB theory and discuss the structures and is considered borderline base (soft base), and is soft acid
MATCHING TYPE. Write the letter after the statement that matches the description. Choices: A. Complex Chelate B. Chelating agent C. EDTA D. Masking Porphine Titration E. Thioglycols Ligand Term used to indicate the determination of a metal in the presence of another metal Substance whose molecules can form several bonds to a single metal ion The product of a complexation reaction is known as the? Added to certain canned foods to remove transition- metal ions that can catalyze the deterioration of the food Inactivate metals such as Hg and Cu which react with the sulfhydryl groups thus allowing the titration of Zn at pH 6
complex formation equilibria with Ag+ for EDTA, CN-, NH3, I-
An EDTA solution was allowed to react with Pb²⁺ to produce 0.25 M PbY²⁻, 2.67×10⁻⁸ M Pb²⁺ and an excess of 0.10 M at equilibrium (K = 1.1×10⁸). What will be the hydronium ion concentration of the resulting solution?
A sample contains Pb2+, Mg2+ and Zn2+. 0.4085 g of the sample is weighed and dissolved. Once dissolved it is with cyanide to form a complex and mask the zinc (Zn2++ 4 CN-→ Zn (CN)4 2-). The Pb2+ and Mg2+ in the solution are titrated with 42.22 mL of EDTA 0.02604 M. Then the Pb complex is treated with another organic ligand that masks Pb and releases EDTA, which is titrated with 19.35 mL of a Mg2+ 0.007657 M solution. For finalize formaldehyde is added to unmask the Zn2+(Zn (CN)4 2- + 4 HCHO + 4 H2O → Zn2+ + 4 HOCH2CN + 4 OH-). The liberated zinc is titrated with EDTA 0.02064 M consuming 28.63 mL. (Data: Pat Pb, 207.22; Pat Mg, 24.31; Pat Zn, 65.4). Find the percentage of the three metals in the sample.