Question

What is the molar concentration of potassium ion in a solution that is `73*"ppm"` with respect to `K_3[Fe(C-=N)_6]`?

Answer 1

`"1 ppm"` specifies `1*mg*L^-1` of solution.........

Explanation:

And thus in `1*L` of solution, we have............

`((73xx10^-3*g)/(329.24*g*mol^-1))/(1*L)=2.21xx10^-5*mol*L^-1` with respect to `K_3[Fe(C-=N)_6]`.

Since that are 3 moles of potassium ion per mole of salt, `[K^+]=6.7xx10^-5*mol*L^-1`.

You might be tempted to argue that I should have accounted for the solution density in these calculations. Even if these data were available, at `"ppm"` concentrations they would make negligible difference, and so may be ignored.

If I dissolved `1*g` of common salt, `NaCl`, in a `1*L` volume of water, what would be the `"ppm"` concentration?