Question

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 in g mol−1: Na : 23, N : 14, K : 39, O : 16, Br : 80, I : 127, F : 19, Ca : 40)

Answer 1

CaF$_2$ does not evolve any gas with concentrated H$_2$SO$_4$.
$\text{NaBr} \rightarrow \text{evolve Br}_2$
$\text{NaNO}_3 \rightarrow \text{evolve NO}_2$
$\text{KI} \rightarrow \text{evolve I}_2$

Answer 2

CaF$_2$ does not evolve any gas with concentrated H$_2$SO$_4$.
$\text{NaBr} \rightarrow \text{evolve Br}_2$
$\text{NaNO}_3 \rightarrow \text{evolve NO}_2$
$\text{KI} \rightarrow \text{evolve I}_2$