Question

If you mix 20.0 mL of 1.00 x 10-4 mol/L NaCl with 20.0 mL of 2.00 x 10-6 mol/L AgNO3 will a precipitate form ? If it does it will be AgCl, which has a Ksp of 1.80 x 10-10.

i'm not quite sure how to figure this out...

Answer 1

You want the solubility quotient which is simply (Ag^+)(Cl^-) in the problem, then compare the product with Ksp. If the product is larger a ppt forms. If the product is smaller, there is no ppt of AgCl. First you must realize that you are mixing solutions; therefore, they will dilute each other.
NaCl is 1.00E-4 x 20 mL/40 mL = 5E-5 M.
AgNO3 is 2.00E-6 x 20 mL/40 mL = 1E-6 M.

So the product is (5E-5)(1E-6) = 5E-11
Compare that with 1.80E-10.

Answer 2

Thank you so much! :)