That's right. Because the expression of precipitation-dissolution equilibrium constant is necessary.
What is divided by "cθ" becomes a pure number, "cθ" and so on.
At the standard concentration, that is, 1mol/L, so S/cθ =
7.3 1× 10^- 17,s=7.3 1× 10^- 17×cθ=
7.3/kloc-0 /×10-17×1= 7.3/kloc-0 /×10-17mol/ml.