Answer:
Hot water.
Explanation:
Hello,
When hot water is added to AgCl and PbCl2 one could identify the following phenomena:
If it is AgCl, the white solid will remain the same after adding the hot water since it is highly insoluble in water.
If it is PbCl2, the solid will dissolve and form a colorless solution after adding the hot water as long as it has a slightly higher solubility in water than the AgCl.
Best regards.