13. (a) if h2s gas is led into a solution of 0.10m fecl2 , what is the highest ph value be controlled in the solution for just no fes precipitate forming?
(b) if h2s gas is led into a solution that is 0.10m each in fecl2 and cucl2 , will fes precipitate from the solution?
(the saturated solution of h2s in water is 0.10m at 25 degrees celsius, 1atm.)

Technically, "quantum theory" is actually just the theory associated with quantum mechanics, ie; the theory of any objects isolated from their surroundings but, because it is very difficult to isolate large objects from their environments, it essentially becomes a theory of the microscopic world of atoms and sub-atomic particles.