Solubilization reactions:
Pb(NO3)2(aq) → Pb2+(aq) + 2 NO3–(aq)
K2SO4(aq) → 2 K+(aq) + SO42–(aq)
Precipitation reaction:
Pb2+(aq) + SO42–(aq) → PbSO4(s)
(Note: precipitation reactions go to completion.)
The net reaction is found by summing all of the above:
Pb(NO3)2(aq) + K2SO4(aq) → PbSO4(s) + 2 K+(aq) + 2 NO3–(aq)
(Note: the soluble products in solution are potassium ions and nitrate ions, not KNO3(aq).)