Using water, how could you distinguish between the white solids kcl an pbcl2

KCl and PbCl2 both are salts having the same white color, however, potassium salts are soluble in water while lead salts are not.
This means that KCl is soluble in water while PbCl2 is not.

So, to distinguish between them, add the same amount of each salt in a beakers containing water (each salt in a separate beaker of course), ans shake the beaker or steer it.
The salt that dissolves in water would be KCl while the salt that doesn't dissolve in water would be PbCl2.