The solution of a sparingly soluble salt Ax By in water is 'S" moles per. the solubility product has the value;
S2
xyyx·Sx+y
xxyySx+y
Sx+y
AxBy(s)⇌x·A(aq. )y++y·B(aq. )x- t = a α teq. (a-s) (x·s) (x·y) ksp=Ay+xBx-y =(x·s)x(y·s)y