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

The atomic number of an element is $11$. Its oxide will be

Sodium oxide $(Na_2O)$ is produced when

Identify $X$ and $Y$, respectively in the following reactions:

Which of the following is a specific photosensitive material?

Identify the correct statements from the following :
$I$. Tendency to form halide hydrates gradually increases from $Be$ to $Ba$ down the group.
$II$. Tendency to form stable superoxides increases from $Li$ to $Cs$ down the group.
$III$. Low solubility of $LiF$ is due to its high lattice energy.
$IV$. Solubility of carbonates of group-$2$ elements increases down the group.