Equivalent conductivity of `BaCl_2,H_2SO_4` and HCl, are `x_1,x_2"and"x_3Scm^(-1)eq^(-1)` at infinite dilution. If conductivity of saturated `BaSo_4` solution is x`Scm^(-1)`, then `K_(sp)` of `BaSO_4` is :