Molar mass of the salt from NaBr, NaNO _ 3 , KI and CaF _ 2 which...

On heating $NaBr$ with concentrated sulphuric acid gives brown colour bromine vapours.

On heating ${NaNO}_{3}$ with concentrated sulphuric acid will release a brown colour ${NO}_{2}$ gas 

On heating ${I}^{-}$ with concentrated sulphuric acid gives a dark purple colour.

On heating with concentrated sulphuric acid with ${CaF}_{2}$ does not give any colour because it produces colourless hydrogen fluoride.Molar mass of ${CaF}_{2}$ is $78 . 07g / mol$