728g sample of Pb/Cd alloy was dissolved in acid and diluted to exactly 500mL. Titration of a 25.00mL aliquot at a pH=10 in an NH4^+/NH3 buffer…

A 1.728g sample of Pb/Cd alloy was dissolved in acid and diluted to exactly 500mL. Titration of a 25.00mL aliquot at a pH=10 in an NH4^+/NH3 buffer required 43.60mL of standard 0.01080M EDTA and involved both cations (Pb^2+ and Cd^2+). The cadmium ion was then masked by using an HCN/NaCN buffer to bring the pH of a second 25.00mL aliquot to 10; 32.70mL of the 0.01080M EDTA standard was used in this titration and involved only the Pb^2+. Calculate the respective percentages of lead and cadmium in the alloy.