Will a precipitate form when you mix solutions of potassium chloride and lead nitrate?

Yes, a white precipitate of lead(II) chloride will form when you mix solutions of potassium chloride and lead nitrate due to the insolubility of lead(II) chloride. The balanced chemical equation for this reaction is:

Pb(NO3)2 + 2KCl → PbCl2 + 2KNO3