A Student Attempts to Separate Cl⁻ and I⁻ from a Solution

question 6

Multiple Choice

A student attempts to separate Cl⁻ and I⁻ from a solution that is 0.05 M Cl⁻ and 0.10 M I⁻ with Pb(NO₃) ₂.As Pb(NO₃) ₂ is added,which anion will precipitate first and what will the concentration of the anion be when the second anion begins to precipitate? K_sp = 1.7 x 10⁻⁵ for PbCl₂ and K_sp = 9.8 x 10⁻⁹ for PbI₂.

• A)iodide precipitates first;0.0068 M iodide
• B)iodide precipitates first;0.0012 M iodide
• C)iodide precipitates first;0.05 M iodide
• D)chloride precipitates first;0.0012 chloride
• E)chloride precipitates first;0.10 M chloride