Titration of iodine with thiosulfate in the presence of CuI yields slightly lower results than expected. Which of the following is the reason for this? A. A certain amount of iodine is adsorbed on the CuI solid. B. CuI is converted to CuSCN to a certain extent. C. The reaction between copper and thiocyanate is unstable. D. A chemical reaction takes place between thiosulfate and copper.

Titration of iodine with thiosulfate in the presence of CuI yields slightly lower results than expected. Which of the following is the reason for this? A. A certain amount of iodine is adsorbed on the CuI solid. B. CuI is converted to CuSCN to a certain extent. C. The reaction between copper and thiocyanate is unstable. D. A chemical reaction takes place between thiosulfate and copper.

Fundamentals Of Analytical Chemistry

9th Edition

ISBN:9781285640686

Author:Skoog

Publisher:Skoog

Chapter26: Molecular Absorption Spectrometry

Section: Chapter Questions

Problem 26.12QAP

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An EDTA solution was prepared by dissolving approximately 4 g of the disodium salt in approximately 1Lof water. An average of 42.35 mL of this solution was required to titrate 50.00-mL aliquots of a standard that contained 0.7682 g of MgCO3 per liter. Titration of a 25.00-mL sample of mineral water at pH 10 required 18.81 mL of the EDTA solution. A 50.00-mL aliquot of the mineral water was rendered strongly alkaline to precipitate the magnesium at Mg(OH)2. Titration with a calcium-specific indicator required 31.54 mL of the EDTA solution. Calculate (a) the molar concentration of the EDTA solution, (b) the concentration of CaCO3 in the mineral water in ppm, (c) the concentration of MgCO3 in the mineral water in ppm. observe significant figures
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