The Ksp of AgCl at 25 oC is 1.6 x 10-10. Consider a solution that is 2.0 x 10-6 M NaCl and 1.0 x 10-4 M AgNO3.

Question

The K_sp of AgCl at 25 ^oC is 1.6 x 10^-10. Consider a solution that is 2.0 x 10^-6 M NaCl and 1.0 x 10^-4 M AgNO₃.

the answer is: Q > K_sp and a precipitate will form

please explain

Answer 1

To determine if a precipitate will or will not form, we calculate Q (the reaction quotient) and compare it to the Ksp. If Q > Ksp, a precipitate WILL form. If less than Ksp, no precipitate forms.

AgCl(s) <===> Ag⁺ + Cl^-

Ksp = [Ag⁺][Cl^-]

[Ag⁺] = 1.0x10^-4 (from the AgNO₃)

[Cl^-] = 2.0x10^-6 (from the NaCl)

Q = [Ag⁺][Cl^-] = (1.0x10^-4)(2.0x10^-6)

Q = 2.0x10^-10

Ksp = 1.6x10^-10

Since the value of Q > Ksp, a precipitate WILL form.