The conductivity of a saturated solution of ${\mathrm{BaSO}}_4$ is $3.06\times {10}^{-6} {\mathrm{ohm}}^{-1} {\mathrm{cm}}^{-1}$ and its equivalent conductance is $1.53 {\mathrm{ohm}}^{-1} {\mathrm{cm}}^2 {\mathrm{equiv}}^{-1}$. The ${\mathrm{K}}_{\mathrm{sp}}$ for ${\mathrm{BaSO}}_4$ will be