Question

When 2.00 L of 1.00 M of `AgNO_3` and 1.25 L of 1.00 M of `CaI_2` fully react, what is the molarity of `Ca^2+`?

Answer 1

For `2AgNO_3(aq) + CaI_2(aq) rarr 2AgI(s)darr + Ca(NO_3)_2(aq)`

Explanation:

The calcium ion, `Ca^(2+)`, which is present in solution as (probably) `[Ca(OH_2)_6]^(2+)`, remains in solution, and expresses its concentration fully because it does not precipitate....

`"Moles of"` `Ca^(2+)=1.25*Lxx1.00*mol*L^-1=1.25*mol`.

The volume of solution is `(2.00+1.25)*L=3.25*L`

And thus concentration of calcium ion is............

`(1.25*mol)/((2.00+1.25)*L)=0.385*mol*L^-1......`

Of course, the silver ion precipitates as a fine yellow powder of `AgI`.........