At   the molar conductances at infinite dilution for the strong electrolytes $\mathrm{NaOH},\mathrm{NaCl}$ and ${\mathrm{BaCl}}_2$ are $248\times {10}^{-4}$, $126\times {10}^{-4}$ and $280\times {10}^{-4}\mathrm{S}.{\mathrm{m}}^2{\mathrm{mol}}^{-1}$ respectively ${\mathrm{\lambda }}_{\mathrm{m}}^0$.  $\mathrm{Ba}{\left(\mathrm{OH}\right)}_2$ in $\mathrm{S}.{\mathrm{m}}^2{\mathrm{mol}}^{-1}$ is