The formula of an oxyacid of phosphorus is $H_3PO_4$. It is a

$H_3BO_3$ is

Draw the structures of $BCl_3.NH_3$ and $AlCl_3$ (dimer).

Borax is converted into crystalline boron by the following steps :
$Borax$ $\xrightarrow{HCl} (X)$ $\xrightarrow{\Delta} B_2O_3$ $\xrightarrow{\Delta, Y} B$
Identify $X$ and $Y$ respectively.

Inorganic benzene reacts with $HCl$ to form a compound $B_3N_3H_9Cl_3$. The protonation occurs at

Relative stability orders of $+1$ and $+3$ oxidation states of $Ga, In, Tl$ are respectively: