Diborane reacts with ammonia to form $X$,which on heating gives $H_2$ and borazine. $X$ is

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.

What are the freezing and boiling points of ammonia $(NH_3)$?

The incorrect statement from the following for borazine is:

Borax is converted into crystalline boron by the following steps:
$Borax$ $\xrightarrow{X} H_3BO_3$ $\xrightarrow{\Delta} B_2O_3$ $\xrightarrow[\Delta]{Y} B$
$X$ and $Y$ are respectively:

Borax is actually made of two tetrahedra and two triangular units joined together and should be written as: $Na_2[B_4O_5(OH)_4] \cdot 8H_2O$. Consider the following statements about borax:
$a.$ Each boron atom has four $B-O$ bonds
$b.$ Each boron atom has three $B-O$ bonds
$c.$ Two boron atoms have four $B-O$ bonds while other two have three $B-O$ bonds
$d.$ Each boron atom has one $-OH$ group
Select correct statement$(s)$: