1. Q Ion Exchange Separations: Complexometric Titrations Dr. Prem D. Sattsangi Copyright © 2009

2. 1.Which complex is stronger? i.e., (has Least tendency to dissociate) (a) [CoCl 4 ] 2- or (b) [CoEDTA] 2- ____________ 2.What are two major purposes of Murexide reagent? _________________________________________________

3. In the application of unknown samples to the column, you are advised to, apply the sample to the column, percolate it in. Add twice, 1 mL of HCl, percolate it in. Then start eluting with large amount of HCl. What will cause the separation to be very poor if, one applies the U.K. sample to the column and immediately starts elution with large amount of HCl? ____________________________________________________

4. Suppose you collected the Copper sample from the column and diluted it to 100 mL in a volumetric flask, but failed to mix it adequately. The titration Results would be______________. (a) Lower than expected, (b) Higher than expected (c) Erratic

5. What is the formula and color of the following complexes? FormulaColor Cobalt chloro complex_______________ ________________ Cobalt aquo complex_______________ ________________ Copper chloro complex_______________ ________________ Copper aquo complex_______________ ________________ What is the purpose of adding ammonia to your sample, before titration? _______________________________________________________

6. If it takes 15.30 mL of 0.0118 M EDTA to titrate 25.0 mL of your cobalt solution, molar concentration of cobalt is_______________. Given, atomic weight of cobalt as 58.93 g/mol, how many grams of cobalt Are present in 100 mL of the solution.

7. How many 5-membered rings can you count in the Co-EDTA complex shown on Page – 3 -, Experiment -7? __________ Draw a structure for EDTA holding Cu 2+ ion