At $25^{\circ}$ the molar conductances at infinite dilution for the strong electrolytes $NaOH,NaCl$ and $Bacl_2$ are $248 \times 10^{-4},126 \times 10^{-4}$ and $280 \times 10^{-4}s.m^2. mol^{-1}$ respectively . $\lambda^{\circ}_mBa(OH)_2$ in $s.m^2 mol^{-1}$:

Question

\[\begin {array} {1 1} (1)\;52.4 \times 10^{-4} & \quad (2)\;524 \times 10^{-4} \\ (3)\;402 \times 10^{-4} & \quad (4)\;262 \times 10^{-4} \end {array}\]