Question

At 25 C the Ksp for PbCl2 is 1.6 × 10^–5.

1.) Calculate Q for the following: 125.0 mL of 0.0300 M Pb(NO3)2 is mixed with 75.0 mL of 0.0200 M NaCl at 25 C

2.) Will a precipitate form from the above reaction?

Answer 1

the Ksp for PbCl2 is 1.6 × 10^–5.

1.) Calculate Q for the following: 125.0 mL of 0.0300 M Pb(NO3)2 is mixed with 75.0 mL of 0.0200 M NaCl at 25 C

Q = [Pb⁺²][Cl^-]²

[Pb⁺²] = Moles of Pb⁺²/ total volume = Molarity of Pb(NO3)2 X volume of Pb(NO3)2 / Total volume

[Pb⁺²] = 0.03 X 125 / 75+125 = 0.01875 M

[Cl-] = Moalrity of NaCl X volume of NaCl / total volume = 0.02 X 75 / 200 =0.0075 M

Q = (0.01875)(0.0075)² = 1.1 X 10^-6

2.) Will a precipitate form from the above reaction?

As Ksp > Q , so no ppt will form