Question

A solution (A) known to contain a high concentration of Cu+2 was diluted by adding 5.00 mL of solution A to a 250.0 mL volumetric flask, filling to the mark, and mixing to make solution C. When 20.00 mL of solution C was titrated with 0.05000 M EDTA, it required 18.50 mL. What was the molar concentration of Cu+2 in solution A?