［J］ for solute in a dilute solution

[Yinhan_Liu_1D]

I am wondering, for example, if the solute is ZnCl2, and in the chemical reaction, its phase is (aq), when we plug in the activity of this part, should we plug in [ZnCl2]^n or [Zn]^n [Cl]^2n?

In the solution, ZnCl2 appears as ions, right?

I would really appreciate your help!

[edward_qiao_3I]

the concentration of Zinc Chloride would go in the denominator, while the concentration of Zinc ion and Chloride ion would go in the numerator.

EDIT: sorry, since Zinc Chloride actually appears as a solid, it is not included in the calculation of the equilibrium constant. Your end equation for chemical equilibrium constant K is K=[Zn][Cl]^2