Answer to Question #67354 in General Chemistry for NUR FATIN IZZATUL

Question

Chromium(III) is slow to react with EDTA (H4Y) and is therefore determined by back-titration. A pharmaceutical preparation containing cromium(III) is analyzed by treating a 2.63g sample with 5.00 mL of 0.0103 M EDTA. Following reaction, the unreacted EDTA is back titrated with 1.32mL of 0.0112M zinc solution. What is the percentage chromium chloride in the pharmaceutical preparation? (FW chromium chloride= 158.36 g/mol).
Cr3++ H4Y → CrY- + 4H+
Zn2+ + H4Y → ZnY2- + 4H+