Question

Which of the following mixtures will result in the formation of a precipitate of `Ag_2SO_4`?

We have the following four solutions:
A `[Ag^+] =` 1e-4
B `[Ag^+] =` 3e-8
C `[SO_4^-2] =` 6e-3
D `[SO_4^-2] =` 5e-7

`K_sp` for `Ag_2SO_4 =` 2.93e-13

A + C
A + D
A + B
B + C
B + D

Answer 1

Well, what is the ion product `Q` in each case....?

Explanation:

We address the equilibrium...

`2Ag^+ +SO_4^(2-) rarr Ag_2SO_4(s)darr`

Now `K_"sp"=[Ag^+]^2[SO_4^(2-)]`...and this is simply an equilibrium expression. And all we have to do is calculate the ion product....`Q=[Ag^+]^2[SO_4^(2-)]`.

If `[Ag^+]^2[SO_4^(2-)]>K_"sp"` then precipitation will occur...

If `[Ag^+]^2[SO_4^(2-)]<=K_"sp"` then the sulfate will remain in solution. I will do the first and then you are on your own....

We try `A.+C.`, `[Ag^+]=1xx10^-4*mol*L^-1`; `[SO_4^(2-)]=6xx10^-3*mol*L^-1`.

The ion product, `Q=(1xx10^-4)^2xx(6xx10^-3)=6.0xx10^-11`.

Now `Q">>"K_"sp"=2.93xx10^-13`...and so precipitation will occur.

And now you use the same procedure on all the other examples. You could post them here....