Match the following compounds in List-$I$ with their uses in List-$II$:

List-$I$ (Compounds)	List-$II$ (Uses)
$A$. Boron-$10$	$I$. Antiseptic
$B$. Borax	$II$. Bullet proof vest
$C$. Boron-fibre	$III$. Neutron absorber
$D$. Orthoboric acid	$IV$. Heat resistance glasses

What are the correct statements about the elements of group $13$ given below?
$(I)$ The stability of $+1$ oxidation state follows the order $Tl > In > Ga$
$(II)$ Boron has the lowest melting point and boiling point as it is a non-metal
$(III)$ Boron shows a maximum covalency of $4$ in its compounds
$(IV)$ The order of atomic radius is $Ga > Al > In$
$(V)$ Aluminium is passive to concentrated nitric acid

In the structure of diborane $(B_2H_6)$,the number of $2$-centre-$2$-electron $(2c-2e)$ bonds is $X$ and the number of $3$-centre-$2$-electron $(3c-2e)$ bonds is $Y$. The value of $(X+Y)$ is:

$AlCl_3$ in water at $pH < 7$ forms

Which of the following boron compounds is the hardest?

Explain the structures of diborane and boric acid.