Which of the following statements is correct?

What is $Z$ in the following reactions?
$BCl_3 + H_2 \xrightarrow[450^{\circ}C]{Cu-Al} X + HCl$
$X \xrightarrow{\text{methylation}} Z$

Which one among the following statements is correct about a solution of borax in water?

$A$ certain salt $X$ gives the following results:
$(i)$ Its aqueous solution is alkaline to litmus.
$(ii)$ It swells up to a glassy material $Y$ on strong heating.
$(iii)$ When conc. $H_2SO_4$ is added to a hot solution of $X$,white crystals of an acid $Z$ separate out.
Identify $X, Y$ and $Z$ and write the equations for the reactions.

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.

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