When sodium is burnt in moist air,the final product will be:

Given below are two statements:
Statement $I$: Lithium and Magnesium do not form superoxide.
Statement $II$: The ionic radius of $Li^{+}$ is larger than the ionic radius of $Mg^{2+}$.
In the light of the above statements,choose the most appropriate answer from the options given below:

$NO_2$ is not obtained on heating:

Which of the following statement$(s)$ is (are) correct?
$(i)$ $LiF$ is less soluble in water
$(ii)$ $NaCl$ is less ionic than $CsCl$
$(iii)$ Formation of alkali metal halide is an endothermic reaction

Which of the following is the correct order of increasing solubility for the given compounds?

The useful by-products obtained in the $Solvay$ process of manufacturing sodium carbonate are: