Which one of the following elements does not form triiodide on reacting with iodine?

$H_3BO_3$ is

Give the industrial preparation for diborane.

Identify the correct statements from the following :
$I$. $Ga_2O_3$ is an amphoteric oxide.
$II$. The dimer of aluminium chloride has three $Al-Cl-Al$ bridge bonds.
$III$. Boron is a very hard refractory solid of high melting temperature.

Match the following reactions in Column-$1$ with their main products in Column-$2$.

Column-$1$ (Reaction)	Column-$2$ (Main product)
$A$. $B_2H_6 + 2CO \longrightarrow$	$I$. $B_2O_3$
$B$. $B_2H_6 + 3O_2 \longrightarrow$	$II$. $2BH_3 \cdot CO$
$C$. $B_2H_6 + 6H_2O \longrightarrow$	$III$. $2H_3BO_3$

The correct match is:

Hydrolysis of $BCl_3$ gives $X$,which on treatment with sodium carbonate produces $Y$. $X$ and $Y$,respectively,are