The reason why alkali metals impart color to the Bunsen burner flame is ......

Which of the following is the correct increasing order for the mentioned property?

The correct statements are:
$I$. The low solubility of $LiF$ is due to its high lattice enthalpy.
$II$. $LiBr$ is soluble in acetone.
$III$. $LiCl$ is soluble in pyridine.
$IV$. The order of melting points of alkali metal halides is $MF > MCl > MBr > MI$.

Which of the following compounds transforms baking soda into baking powder?

$A$ chloride is soluble in cold water. When it is placed on a $Pt$ wire and heated in a Bunsen flame,it does not impart any characteristic color to the flame. Which of the following cations is present?

In Solvay process,$NH_3$ is recovered when the solution containing $NH_4Cl$ is treated with compound ' $X$ '. What is ' $X$ ' ?