AgNO3 is added to a solution containing Cl- and CrO42- in order to separate the ions. If the Cl- and CrO42- concentrations are 0.020 and 0.010 M, respectively, what are the minimum Ag+ concentrations required to precipitate out the anions?

The minimum concentrations required to precipitate out the anions is M.

Explanation:

We know that,

  for AgCl is

and,   for is

Now, we will calculate the concentration of  at which these ions precipitate out are as follows.

For AgCl :

             =

             = M

For   :

              =

              =

            = M

This shows that concentration of  ions in AgCl is less than the concentration of AgCl will precipitate first.