The Tl in a 9.76-g sample of rodenticide was oxidized to the trivalent state and treated with an unmeasured excess of Mg/EDTA solution. The reaction is Tl+3 + MgY-2 → TlY- + Mg+2 . Molecular mass:  Tl2SO4  =  504.8 a. Titration of the liberated Mg2+ required 13.34-mL of 0.03560 N EDTA. The type of titration involved in the assay is (direct/indirect/residual) ______? b. percentage of Tl2SO4 in the sample is __________ %?

A 1.000 mL aliquot of a solution containing Cu²+ and Ni²+ is treated with 25.00 mL of a 0.03703 M EDTA solution. The solution is then back titrated with 0.02138 M Zn²+ solution at a pH of 5. A volume of 22.13 mL of the Zn²+ solution was needed to reach the xylenol orange end point. A 2.000 mL aliquot of the Cu²+ and Ni²+ solution is fed through an ion-exchange column that retains Ni²+. The Cu²+ that passed through the column is treated with 25.00 mL of 0.03703 M EDTA. This solution required 18.53 mL of 0.02138 M Zn²+ for back titration. The Ni²+ extracted from the column was treated witn 25.00 mL of 0.03703 M EDTA. How many milliliters of 0.02138 M Zn²+ is required for the back titration of the Ni²+ solution? volume: mL

What is the mass of pure dry CaCO3 (MW: 100.0869 g/mol) standard used in the standardization of EDTA solution? Assume that 1.758 M EDTA solution was computed based on the titration of CaCO3 standard. The volume of titrant needed to reach the endpoint was 35.00 mL.   Ca2+ + Y4- →  CaY2-         0.1500 g                       5.630 g     6.158 g                                     0.6158 g

Hh.88.