$B_4C$ (boron carbide) is used except:

Write balanced chemical equations for the following reactions:
$(i)$ $BF_3 + LiH \rightarrow$
$(ii)$ $B_2H_6 + H_2O \rightarrow$
$(iii)$ $NaH + B_2H_6 \rightarrow$
$(iv)$ $H_3BO_3 \xrightarrow{\Delta}$
$(v)$ $Al + NaOH \rightarrow$
$(vi)$ $B_2H_6 + NH_3 \rightarrow$

Match Column-$I$ with Column-$II$ :

Column-$I$	Column-$II$
$A$. $Bi^{+3} \to (BiO)^{+}$	$P$. Heat
$B$. $[AlO_2]^{-} \to Al(OH)_3$	$Q$. Hydrolysis
$C$. $SiO_4^{-4} \to Si_2O_7^{-6}$	$R$. Acidification
$D$. $(B_4O_7)^{-2} \to [B(OH)_3]$	$S$. Dilution with water

What is $Z$ in the following reactions?

The correct orders among the following are
$A$. Atomic radius $: B < Al < Ga < In < Tl$
$B$. Electronegativity $: Al < Ga < In < Tl < B$
$C$. Density $: Tl < In < Ga < Al < B$
$D$. $1^{st}$ Ionisation Energy $: In < Al < Ga < Tl < B$
Choose the correct answer from the options given below $:$

Explain why the following compounds behave as Lewis acids?
$(A)$ $BCl_3$
$(B)$ $AlCl_3$