Which element belongs to the family of elements that also includes the element gallium?

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

Substance $X$ reacts with an aqueous solution of $NaOH$ to form $Y$ and releases $H_2$ gas. When an aqueous solution of $Y$ is heated at $323 \; K - 333 \; K$ and $CO_2$ gas is passed through it,it yields $Al_2O_3 \cdot xH_2O$ (often represented as $Al(OH)_3$) and $Z$. Heating $Z$ at $1200^{\circ}C$ produces $Al_2O_3$. Identify $X, Y,$ and $Z$.

White fumes appear around the bottle of anhydrous aluminium chloride. Give reason.

Two elements $X$ and $Y$ combine separately with a highly electropositive metal to form binary compounds,which upon hydrolysis yield borane and silane,respectively. What are $X$ and $Y$?

Describe the physical properties of $B$ and $Al$.