Chemistry Question of the Day

PbF2(s), which is slightly soluble in water, is dissolved in water to form a saturated solution in equilibrium with solid PbF2. Which of the following will cause additional PbF2(s) to dissolve?

1. Adding HNO3
2. Adding Pb(NO3)2
3. Adding a seed crystal
4. Adding solid PbF2
5. Evaporating some of the water to decrease the volume of solution