Solutions: Equilibrium of Salts in Solution

[DrDu]

Come on, try to work out something yourself!

What do you mean? Can you just write the one equation?

The problem with Na+ conservation is that Na+ is also contributed to by another salt.

Of course, but $c_0(NaHSO3)$ is known as it is completely dissolved, at least, that's what you were assuming.

 

[Big-Daddy]

I'm sorry, I've tried and I don't know the answer.

 

[DrDu]

Set up the conservation equation for Na and use it to eliminate c0(Na2SO3)=n0(Na2SO3)/V, where n0(Na2SO3) is the total amount of dissolved Na2SO3) (i.e. c0(Na2SO3) is an additional variable in your system).

 

[Big-Daddy]

Ok, what if I then added K2SO3 up to saturation? Is it

Mass Balance for S: (1/2) * [K⁺] + (1/2) * ([Na+] - c₀[NaHSO3]) + c₀[NaHSO3] = [SO2] + [HSO₃^-] + [SO₃^2-]