Chapter 35, Problem 2ASA

Why do you add NaHCO3 to the sample solutions in the determination of chloride by the Mohr Method (Analytical Chemistry)

You are given a table of [CN-] standard solutions of different concentration. A 25 mL aliquot of each standard solution was added with Fe(NO3)3 to form a colored complex[Fe(CN)6]3-(aq). Each standard solution was then diluted to a total volume of50.0 mL. [CN–] prior to dilution, M [CN-] final M 0 0 0.04   0.1   0.16   0.24   0.32   0.4   What are the new concentrations for the standard solutions? Please show solutions.

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.

Sketch a photometric titration curve for the titration of Sn2+ with MnO4 . What color radiation should be used for this titration? Explain.

What amount of ammonia (moles) must be added to dissolve 0.050 mol of AgCl suspended in 1.0 L of water?

What mass of ZnS (Ksp = 2.5 1022) will dissolve in 300.0 mL of 0.050 M Zn(NO3)2? Ignore the basic properties of S2.

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?

A solution contains 1.0 x 10−5 M Na3PO4. What is the minimum concentration of AgNO3 that would cause precipitation of solid Ag3PO4? (Ksp = 1.8 x 10−18)

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. 5.44B. 8.63C. 2.89D. 7.89