The Ksp of AgCl is 1.8 * 10-10. How do you know that mixing equal amounts of 0.04M solution of AgNO3 and 0.002M solution of NaCl will lead to the formation of a precipitate?

AgNO₃ + NaCl = NaNO₃ + AgCl↓

c (AgNO₃) = 0.04 mol/L

c (NaCl) = 0.002 mol/L ⇒ n (AgCl) / L=0.002 mol/L

Ksp=[Ag⁺][Cl⁻]

the solubility of silver chloride

√Ksp=1.34*10⁻⁵ mol/L

n (AgCl) / L>√Ksp the precipitate of silver chloride is formed