Molar mass of the salt from NaBr, NaNO_3, KI and CaF_2 which does not evolve coloured vapours on heating with concentrated H_2 SO_4 is ____ g mol^-1.…

Molar mass of the salt from $\displaystyle \mathrm{NaBr}, \mathrm{NaNO}_3, \mathrm{KI}$ and $\displaystyle \mathrm{CaF}_2$ which does not evolve coloured vapours on heating with concentrated $\displaystyle \mathrm{H}_2 \mathrm{SO}_4$ is $\displaystyle \_\_\_\_$ $\displaystyle \mathrm{g} \mathrm{mol}^{-1}$. (Molar mass in $\displaystyle \mathrm{g} \mathrm{mol}^{-1}: \mathrm{Na}: 23, \mathrm{~N}: 14, \mathrm{~K}: 39, \mathrm{O}: 16, \mathrm{Br}: 80, \mathrm{I}: 127, \mathrm{~F}: 19, \mathrm{Ca}$ : $\displaystyle 40$)