Which of the following is isostructural with graphite?

The element which exists in liquid state for a wide range of temperature and can be used for measuring high temperature is :-

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

What are electron-deficient compounds? Are $BCl_3$ and $SiCl_4$ electron-deficient species?

Which of the following is the correct decreasing order of Lewis acid strength of boron halides?

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