Question 1
How many moles of NaF must be dissolved in 1.00 liter of a saturated solution of PbF
2 at 25°C to reduce the [Pb
2+] to 1.0 × 10
–6 M? The K
sp for PbF
2 at 25 °C is 4.0 × 10
–8.
Question 2
NaCl is added slowly to a solution that is 0.010 M each in Cu
+, Ag
+, and Au
+. The K
sp's for CuCl, AgCl, and AuCl are 1.9 × 10
–7, 1.8 × 10
–10, and 2.0 × 10
–13, respectively. Which compound will precipitate first?