The frequency of the radiation emitted by alkali metals in the flame test follows the order:

What is the product of the reaction between aluminium and aqueous $NaOH$?

Why is $Li_{2}CO_{3}$ decomposed at a lower temperature whereas $Na_{2}CO_{3}$ at higher temperature?

Which of the following metal oxides decomposes upon heating?

Which of the following is a specific photosensitive material?

Which of the following is $CORRECT$ regarding alkali metals?
$I$. Pure $NaCl$ is hygroscopic
$II$. $(n - 1)d$ subshell is vacant only
$III$. Aqueous $NaHCO_3$ solution is more basic than $Na_2CO_3$ solution
$IV$. Both $Li^{+}$ and $Mg^{2+}$ do not form alums