Three solutions are mixed together to form a single solution. One contains 0.2 mol Pb(CH3COO)2, the second contains 0.1 mol Na2S, and the third contains 0.1 mol CaCl2. Write the net ionic equations for the precipitation reaction or reactions that occur.

Answer 1

Pb^2+(aq) + S^=(aq) ==> PbS(s)
Pb^2+(aq) + 2Cl^-(aq) ==> PbCl2(s)
Note: Both reactions will not take place unless there is enough Pb^2+ to ppt BOTH. PbS will ppt first and if there is enough lead ion present, PbCl2 will ppt next.