Which of the following is true for an element belonging to group $13$ of the periodic table?

Which of the following imparts a green colour to the burner flame?

Which one of the following oxides dissolves in both hydrochloric acid and sodium hydroxide?

Aluminium $(III)$ chloride forms a dimer because ........

$A$ black coloured element with $ns^2 np^1$ outer electronic configuration cannot react with air in its crystalline form. However, in amorphous form, it gives an oxide in air which is acidic in nature. Identify the element.

Match the following:

Column $I$	Column $II$
$A$. $Bi^{3+} \longrightarrow (BiO)^{+}$	$P$. Heat
$B$. $[AlO_2]^{-} \longrightarrow Al(OH)_3$	$Q$. Hydrolysis
$C$. $SiO_4^{4-} \longrightarrow Si_2O_7^{6-}$	$R$. Acidification
$D$. $(B_4O_7^{2-}) \longrightarrow [B(OH)_3]$	$S$. Dilution by water