The nitrate of which metal leaves a metallic globule upon strong heating?

The photoelectric effect is maximum in which of the following elements?

Which cannot be used to generate $H_{2}$?

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.

Explain how industrial production of sodium hydroxide is carried out by the Castner-Kellner cell.

Which of the following statements is incorrect for alkali metals?