A solution contains both Ca 2+ and Pb 2+ ions. A 50.0-mL sample of this solution was

Question:

A solution contains both Ca²⁺ and Pb²⁺ ions. A 50.0-mL sample of this solution was treated with 0.528 M NaF, and 53.8 mL of the NaF solution was needed to precipitate all of the Ca²⁺ and Pb²⁺ as CaF₂(s) and PbF₂(s). The precipitate was dried and weighed and had a total mass of 3.141g. What was the concentration of Ca²⁺ in the original solution?